CN110325810B

CN110325810B - Vapor chamber, electronic device, metal sheet for vapor chamber, and method for manufacturing vapor chamber

Info

Publication number: CN110325810B
Application number: CN201880013745.8A
Authority: CN
Inventors: 高桥伸一郎; 平田贤郎; 太田贵之; 桥本大蔵; 竹松清隆
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2017-02-24
Filing date: 2018-02-23
Publication date: 2021-05-14
Anticipated expiration: 2038-02-23
Also published as: US11578927B2; JP6853962B2; JP2023052131A; KR20230117628A; KR102442311B1; JP6587164B2; JP7459922B2; JP7205597B2; US11747090B2; KR102561617B1; JP2024016179A; WO2018155641A1; JP2022000606A; US20230358481A1; TW202321640A; TWI736745B; CN113237368A; KR20220125721A; TW201842296A; US20220107136A1

Abstract

The steam chamber of the present invention has a flow channel section having a 1 st main flow channel, a 2 nd main flow channel, and a 3 rd main flow channel. A1 st projection row is provided between a 1 st main flow groove and a 2 nd main flow groove, and the 1 st projection row includes a plurality of 1 st projections arranged with a 1 st communication groove interposed therebetween. A2 nd projection row including a plurality of 2 nd projections arranged with a 2 nd communication groove interposed therebetween is provided between the 2 nd main flow groove and the 3 rd main flow groove. The 2 nd main flow groove includes a 1 st intersection where at least a part of the 1 st communication groove faces the 2 nd convex portion and a 2 nd intersection where at least a part of the 2 nd communication groove faces the 1 st convex portion.

Description

Vapor chamber, electronic device, metal sheet for vapor chamber, and method for manufacturing vapor chamber

Technical Field

The present invention relates to a vapor chamber (vapor chamber) having a sealed space in which a working fluid is sealed, an electronic device, a metal sheet for the vapor chamber, and a method for manufacturing the vapor chamber.

Background

Devices that generate heat such as a Central Processing Unit (CPU), a Light Emitting Diode (LED), and a power semiconductor used in mobile terminals such as mobile terminals and tablet terminals are cooled by a heat radiation member such as a heat pipe (see, for example, patent documents 1 to 5). In recent years, in order to reduce the thickness of mobile terminals and the like, the heat radiating member is also required to be reduced in thickness, and a vapor chamber capable of being reduced in thickness as compared with a heat pipe is being developed. The working fluid is sealed in the vapor chamber, absorbs heat of the device, and is released to the outside, thereby cooling the device.

More specifically, the working fluid in the vapor chamber is heated and evaporated from the device at a portion (evaporation portion) close to the device to become vapor, and then the vapor moves to a position away from the evaporation portion to be cooled and condensed to become liquid. A liquid flow path portion as a capillary structure (wick) is provided in the vapor chamber, and the liquid working fluid is transported to the evaporation portion through the liquid flow path portion, and is again heated and evaporated in the evaporation portion. In this way, the working fluid flows back into the vapor chamber while repeating phase change, i.e., evaporation and condensation, thereby transferring heat from the device and improving heat dissipation efficiency.

However, the liquid flow path portion has a plurality of grooves extending in the 1 st direction. The working fluid receives capillary action to obtain a propulsive force toward the evaporation portion, and passes through the groove toward the evaporation portion. In addition, another groove extending in the 2 nd direction orthogonal to the 1 st direction is provided for the working fluid to flow between the adjacent grooves. In this way, the plurality of grooves are formed in a lattice shape in the liquid flow path portion, and the working fluid is uniformly distributed in the liquid flow path portion.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-59693

Patent document 2: japanese laid-open patent publication No. 2015-88882

Patent document 3: japanese patent laid-open publication No. 2016-17702

Patent document 4: japanese patent laid-open publication No. 2016-50682

Patent document 5: japanese patent laid-open publication No. 2016-205693

Disclosure of Invention

Problems to be solved by the invention

However, when a plurality of grooves are formed in a lattice shape, a problem arises due to the pressure received from the outside air.

That is, the steam chamber is formed of two metal pieces, and the groove is formed in at least one of the metal pieces. Thus, the thickness of the metal material is reduced in the portion of the metal sheet where the groove is formed. Since the space in the liquid flow path portion is depressurized, the metal sheet receives a pressure in a direction of sinking inward from the outside air. Therefore, the metal piece may be recessed inward along the groove. In particular, as described above, when the vapor chamber is made thin, the thickness of the metal piece is reduced and the metal piece is easily dented.

In the crossing portion where the mutually orthogonal grooves cross each other, when the groove of the metal sheet along the 2 nd direction is recessed, the recess may be formed to cross the groove along the 1 st direction. In this case, the channel cross-sectional area of the groove along the 1 st direction becomes smaller, and the channel resistance of the working fluid may increase. Therefore, the function of transporting the liquid working fluid to the evaporation portion is reduced, and the supply amount of the working fluid to the evaporation portion is reduced. In this case, there is a problem that the amount of heat transferred from the evaporation unit decreases, and the heat transfer efficiency decreases.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a vapor chamber, an electronic device, a metal sheet for a vapor chamber, and a method for manufacturing a vapor chamber, which can secure a flow path cross-sectional area of a liquid flow path portion, improve a function of transporting a liquid working fluid, and improve heat transport efficiency.

Means for solving the problem

The present invention provides a steam chamber, wherein working fluid is sealed, and the steam chamber comprises:

1 st metal sheet;

the 2 nd metal sheet is arranged on the 1 st metal sheet; and

a sealed space provided between the 1 st metal piece and the 2 nd metal piece and having a vapor passage portion through which vapor of the working fluid passes and a liquid passage portion through which liquid working fluid passes,

the liquid flow path portion is provided on a surface of the 1 st metal piece on the 2 nd metal piece side,

the liquid flow path portion has a 1 st main flow channel, a 2 nd main flow channel and a 3 rd main flow channel which extend in a 1 st direction and through which the liquid working fluid passes,

the 1 st main flow channel, the 2 nd main flow channel, and the 3 rd main flow channel are arranged in this order in a 2 nd direction orthogonal to the 1 st direction,

a 1 st projection row including a plurality of 1 st projections arranged in the 1 st direction with a 1 st communication groove interposed therebetween is provided between the 1 st main flow groove and the 2 nd main flow groove,

a 2 nd protrusion row including a plurality of 2 nd protrusions aligned in the 1 st direction with a 2 nd communication groove interposed therebetween is provided between the 2 nd main flow groove and the 3 rd main flow groove,

the 1 st communication groove communicates the 1 st main flow groove with the 2 nd main flow groove,

the 2 nd communication groove communicates the 2 nd main flow groove with the 3 rd main flow groove,

the 2 nd main flow channel includes: a 1 st intersection portion in which at least a part of the 1 st communication groove faces the 2 nd convex portion; and a 2 nd intersection portion in which at least a part of the 2 nd communication groove faces the 1 st projection.

In the above-mentioned steam chamber, it is also possible to,

the 1 st intersection and the 2 nd intersection of the 2 nd main flow channel are adjacent to each other.

In the vapor chamber, it is also possible to,

the 2 nd main flow channel includes a plurality of the 1 st intersections and a plurality of the 2 nd intersections,

the 1 st intersection and the 2 nd intersection of the 2 nd main flow channel are alternately arranged.

In the vapor chamber, it is also possible to,

the liquid channel part further includes a 4 th main flow channel through which the liquid working liquid extending in the 1 st direction passes,

the 4 th main flow channel is disposed on the opposite side of the 2 nd main flow channel side from the 3 rd main flow channel,

a 3 rd projection row including a plurality of 3 rd projections arranged in the 1 st direction with a 3 rd communication groove interposed therebetween is provided between the 3 rd main flow groove and the 4 th main flow groove,

the 3 rd communication groove communicates the 3 rd main flow groove with the 4 th main flow groove,

the 3 rd main flow channel comprises: a 1 st intersection portion where at least a part of the 2 nd communication groove faces the 3 rd convex portion; and a 2 nd intersection portion in which at least a part of the 3 rd communication groove faces the 2 nd convex portion.

In the vapor chamber, it is also possible to,

the 1 st intersection and the 2 nd intersection of the 3 rd main flow channel are adjacent to each other.

In the vapor chamber, it is also possible to,

the 3 rd main flow channel includes a plurality of the 1 st intersections and a plurality of the 2 nd intersections,

the 1 st intersection and the 2 nd intersection of the 3 rd main flow channel are alternately arranged.

In the vapor chamber, it is also possible to,

the 2 nd metal piece has a flat contact surface that contacts a surface of the 1 st metal piece on the 2 nd metal piece side and covers the 2 nd main flow channel.

In the vapor chamber, it is also possible to,

the width of the 2 nd main flow groove is larger than the width of the 1 st protrusion and the width of the 2 nd protrusion.

In the vapor chamber, it is also possible to,

the width of the 1 st communication groove is larger than the width of the 1 st main flow groove and the width of the 2 nd main flow groove,

the width of the 2 nd communication groove is larger than the width of the 2 nd main flow groove and the width of the 3 rd main flow groove.

The depth of the 1 st communication groove is deeper than the depth of the 1 st main flow groove and the depth of the 2 nd main flow groove,

the depth of the 2 nd communication groove is deeper than the depth of the 2 nd main flow groove and the depth of the 3 rd main flow groove.

In the vapor chamber, it is also possible to,

the depth of the 1 st intersection and the depth of the 2 nd intersection of the 2 nd main flow channel are deeper than the depth of a portion between the 1 st projection and the 2 nd projection adjacent to each other in the 2 nd main flow channel.

In the vapor chamber, it is also possible to,

the depth of the 1 st intersection and the depth of the 2 nd intersection of the 2 nd main flow channel are deeper than the depth of the 1 st communication channel and the depth of the 2 nd communication channel.

In the vapor chamber, it is also possible to,

the 1 st convex part comprises a pair of 1 st convex part end parts arranged at both ends in the 1 st direction and a 1 st convex part middle part arranged between the pair of 1 st convex part end parts,

the width of the 1 st convex part middle part is smaller than the width of the 1 st convex part end part.

In the vapor chamber, it is also possible to,

and a bent part with a round angle is arranged at the corner of the 1 st convex part.

In the vapor chamber, it is also possible to,

the 2 nd metal piece has a plurality of main flow groove projections projecting from the 1 st metal piece-side surface of the 2 nd metal piece toward the 1 st main flow groove, the 2 nd main flow groove, and the 3 rd main flow groove of the 1 st metal piece, respectively.

In the vapor chamber, it is also possible to,

the cross section of the main flow groove convex part is formed into a curved shape.

In the vapor chamber, it is also possible to,

the 2 nd metal piece has a plurality of communication groove convex portions protruding from the 1 st metal piece side surface of the 2 nd metal piece toward the 1 st communication groove and the 2 nd communication groove of the 1 st metal piece, respectively.

In the vapor chamber, it is also possible to,

the cross section of the convex part of the communication groove is formed into a curved shape.

Further, the present invention provides an electronic device including:

a housing;

a device housed within the housing; and

the vapor chamber is in thermal contact with the device.

In addition, the present invention provides a metal sheet for a steam chamber, which is used for the steam chamber,

the steam chamber is sealed with a working fluid and has a sealed space including a steam flow path portion through which steam of the working fluid passes and a liquid flow path portion through which the liquid working fluid passes,

the metal sheet for a steam chamber includes:

the 1 st surface; and

a 2 nd surface provided on the opposite side of the 1 st surface,

the liquid channel part is provided on the 1 st surface,

In addition, the present invention provides a method for manufacturing a vapor chamber,

the steam chamber has a sealed space provided between the 1 st metal piece and the 2 nd metal piece, filled with the working fluid, and including a steam passage portion through which steam of the working fluid passes and a liquid passage portion through which the liquid working fluid passes,

the method for manufacturing the steam chamber comprises the following steps:

a half-etching step of forming the liquid channel portion on the surface of the 1 st metal piece on the 2 nd metal piece side by half-etching;

a joining step of joining the 1 st metal piece and the 2 nd metal piece to form the sealed space between the 1 st metal piece and the 2 nd metal piece; and

a sealing step of sealing the working fluid in the sealed space,

Effects of the invention

According to the present invention, the cross-sectional area of the liquid flow path portion can be ensured, the function of transporting the liquid working fluid can be improved, and the heat transport efficiency can be improved.

Drawings

Fig. 1 is a schematic perspective view illustrating an electronic apparatus according to embodiment 1 of the present invention.

Fig. 2 is a plan view showing a vapor chamber according to embodiment 1 of the present invention.

Fig. 3 is a sectional view taken along line a-a showing the vapor chamber of fig. 2.

Fig. 4 is a top view of the lower metal sheet of fig. 2.

Fig. 5 is a bottom view of the upper metal sheet of fig. 2.

Fig. 6 is an enlarged plan view showing the liquid flow path portion of fig. 4.

Fig. 7 is a cross-sectional view of the upper flow path wall portion of the upper metal sheet shown in addition to the cross-sectional view taken along line B-B in fig. 6.

Fig. 8 is a diagram for explaining a preparation process of a lower metal sheet in the vapor chamber manufacturing method according to embodiment 1 of the present invention.

Fig. 9 is a diagram for explaining a 1 st half etching step of the lower metal sheet in the vapor chamber manufacturing method according to embodiment 1 of the present invention.

Fig. 10 is a diagram for explaining the 2 nd half-etching step of the lower metal sheet in the vapor chamber manufacturing method according to embodiment 1 of the present invention.

Fig. 11 is a diagram for explaining a temporary fixing step in the method for manufacturing a vapor chamber according to embodiment 1 of the present invention.

Fig. 12 is a diagram for explaining a permanent joining step in the method for manufacturing a vapor chamber according to embodiment 1 of the present invention.

Fig. 13 is a diagram for explaining a working fluid sealing step in the method for manufacturing a vapor chamber according to embodiment 1 of the present invention.

Fig. 14 is a view showing a modification of fig. 6.

Fig. 15 is a plan view showing a modification of the liquid flow path convex portion shown in fig. 6.

Fig. 16 is a plan view showing another modification of the liquid flow path convex portion shown in fig. 6.

Fig. 17 is a view showing another modification of fig. 6.

Fig. 18 is a view showing another modification of fig. 3.

Fig. 19 is an enlarged plan view showing a liquid flow path portion in a vapor chamber in embodiment 2 of the present invention.

FIG. 20 is a cross-sectional view of the upper channel wall portion of the upper metal sheet shown in addition to the cross-sectional view taken along line C-C in FIG. 19.

FIG. 21 is a cross-sectional view of the upper channel wall portion of the upper metal sheet shown in addition to the cross-sectional view taken along line D-D in FIG. 19.

Fig. 22 is a cross-sectional view of the upper flow path wall portion of the upper metal sheet shown in addition to the cross-sectional view taken along line E-E in fig. 19.

Fig. 23 is an enlarged sectional view showing a main flow groove protrusion in a steam chamber according to embodiment 3 of the present invention, and corresponds to fig. 20.

Fig. 24 is an enlarged sectional view showing a communication groove protrusion in the steam chamber according to embodiment 3 of the present invention, and corresponds to fig. 21.

Fig. 25 is an enlarged sectional view showing a communication groove protrusion in the steam chamber according to embodiment 3 of the present invention, and corresponds to fig. 22.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, the aspect ratio, and the like are appropriately changed and exaggerated for the convenience of illustration and ease of understanding.

(embodiment 1)

A vapor chamber, an electronic device, a metal sheet for a vapor chamber, and a method for manufacturing a vapor chamber in embodiment 1 of the present invention will be described with reference to fig. 1 to 18. The steam chamber 1 in the present embodiment is a device mounted on the electronic device E for cooling the device D as a heat generating body housed in the electronic device E. Examples of the device D include electronic devices (devices to be cooled) that generate heat such as a Central Processing Unit (CPU), a Light Emitting Diode (LED), and a power transistor, which are used in mobile terminals such as mobile terminals and tablet terminals.

First, the electronic device E having the vapor chamber 1 of the present embodiment mounted thereon will be described by taking a tablet terminal as an example. As shown in fig. 1, an electronic device E (tablet terminal) includes a housing H, a device D housed in the housing H, and a steam chamber 1. In the electronic apparatus E shown in fig. 1, a touch panel display TD is provided on the front surface of the housing H. The vapor chamber 1 is housed within a housing H, configured to be in thermal contact with the device D. Thus, the vapor chamber 1 can receive heat generated in the device D when the electronic apparatus E is used. The heat received by the steam chamber 1 is released to the outside of the steam chamber 1 via the working fluid 2 described later. Thus, the device D is effectively cooled. When the electronic device E is a tablet terminal, the device D corresponds to a central processing unit or the like.

Next, the steam chamber 1 of the present embodiment will be explained. The vapor chamber 1 has a sealed space 3 in which the working fluid 2 is sealed, and the device D of the electronic apparatus E described above is efficiently cooled by repeating phase change with the working fluid 2 in the sealed space 3.

The steam chamber 1 is formed into a substantially thin flat plate shape. The planar shape of the steam chamber 1 is arbitrary, but may be a rectangular shape as shown in fig. 2. In this case, the steam chamber 1 has four linear

outer edges

1a, 1b constituting an out-of-plane contour. Two of the outer edges 1a are formed along a 1 st direction X described later, and the remaining two outer edges 1b are formed along a 2 nd direction Y described later. The planar shape of the steam chamber 1 may be, for example, a rectangle having one side of 1cm and the other side of 3cm, or a square having one side of 15cm, and the planar size of the steam chamber 1 may be arbitrary.

As shown in fig. 2 and 3, the steam chamber 1 includes a lower metal sheet 10 (1 st metal sheet) having an upper surface 10a (1 st surface) and a lower surface 10b (2 nd surface) provided on the opposite side of the upper surface 10a, and an upper metal sheet 20 (2 nd metal sheet) provided on the lower metal sheet 10. The lower metal piece 10 and the upper metal piece 20 both correspond to metal pieces for a steam chamber. The upper metal sheet 20 has a lower surface 20a (surface on the lower metal sheet 10 side) overlapping with the upper surface 10a (surface on the upper metal sheet 20 side) of the lower metal sheet 10, and an upper surface 20b provided on the opposite side of the lower surface 20 a. A device D as a cooling target is mounted on the lower surface 10b of the lower metal sheet 10 (particularly, the lower surface of an evaporation unit 11 described later).

The steam chamber 1 has a thickness of, for example, 0.1mm to 1.0 mm. In fig. 3, when the thickness T1 of the lower metal piece 10 and the thickness T2 of the upper metal piece 20 are equal to each other, the thickness T1 of the lower metal piece 10 and the thickness T2 of the upper metal piece 20 may not be equal to each other.

A sealed space 3 in which the working fluid 2 is sealed is formed between the lower metal piece 10 and the upper metal piece 20. In the present embodiment, the sealed space 3 includes a vapor flow path portion (a lower vapor flow path concave portion 12 and an upper vapor flow path concave portion 21 described later) through which vapor mainly of the working fluid 2 passes, and a liquid flow path portion 30 through which the liquid working fluid 2 mainly passes. Examples of the working liquid 2 include pure water, ethanol, methanol, and acetone.

The lower metal sheet 10 and the upper metal sheet 20 are joined by diffusion bonding described later. In the embodiment shown in fig. 2 and 3, the lower metal piece 10 and the upper metal piece 20 are both formed in a rectangular shape in a plan view, but the invention is not limited thereto. Here, the plan view is a state viewed from a direction perpendicular to a surface (the lower surface 10b of the lower metal sheet 10) on which the heat of the vapor chamber 1 is received from the device D and a surface (the upper surface 20b of the upper metal sheet 20) on which the received heat is released, and corresponds to a state in which the vapor chamber 1 is viewed from above (see fig. 2) or a state in which the vapor chamber is viewed from below, for example.

In addition, when the steam chamber 1 is provided in the portable terminal, the vertical relationship between the lower metal piece 10 and the upper metal piece 20 may be broken depending on the posture of the portable terminal. In the present embodiment, for convenience, the metal sheet that receives heat from the device D is referred to as the lower metal sheet 10, the metal sheet that emits the received heat is referred to as the upper metal sheet 20, and the description will be made with the lower metal sheet 10 disposed on the lower side and the upper metal sheet 20 disposed on the upper side.

As shown in fig. 4, the lower metal sheet 10 includes an evaporation portion 11 where the working fluid 2 evaporates to generate steam, and a lower steam flow path concave portion 12 (1 st steam flow path concave portion) provided on the upper surface 10a and formed in a rectangular shape in a plan view. The lower steam flow path concave portion 12 constitutes a part of the sealed space 3, and is mainly configured to allow steam generated in the evaporation portion 11 to pass therethrough.

The evaporation portion 11 is disposed in the lower steam flow path concave portion 12, and the steam in the lower steam flow path concave portion 12 is diffused in a direction away from the evaporation portion 11, and most of the steam is sent to a peripheral portion having a relatively low temperature. The evaporation unit 11 is a portion that receives heat from the device D attached to the lower surface 10b of the lower metal sheet 10 and evaporates the working fluid 2 in the sealed space 3. Therefore, the term "evaporation portion 11" is not limited to a portion overlapping the device D, and is also used as a concept of a portion where the working fluid 2 can be evaporated even if the portion does not overlap the device D. Here, the evaporation portion 11 can be provided at any position of the lower metal sheet 10, and fig. 2 and 4 show an example of being provided at the center portion of the lower metal sheet 10. In this case, the operation of the steam chamber 1 can be stabilized without depending on the posture of the mobile terminal in which the steam chamber 1 is provided.

In the present embodiment, as shown in fig. 3 and 4, a plurality of lower flow path wall portions 13 (1 st flow path wall portion) protruding upward (in a direction perpendicular to the bottom surface 12 a) from a bottom surface 12a (described later) of the lower steam flow path concave portion 12 are provided in the lower steam flow path concave portion 12 of the lower metal sheet 10. In the present embodiment, an example is shown in which the lower flow path wall portion 13 extends in an elongated shape along the 1 st direction X (longitudinal direction, left-right direction in fig. 4) of the steam chamber 1. The lower flow path wall portion 13 includes an upper surface 13a (the 1 st contact surface, the projecting end surface) that contacts a lower surface 22a of an upper flow path wall portion 22 described later. The upper surface 13a is a surface which is not etched by two etching steps described later, and is formed on the same plane as the upper surface 10a of the lower metal sheet 10. The lower flow path wall portions 13 are arranged in parallel with each other at equal intervals. Thus, the steam of the working fluid 2 flows around each lower flow path wall portion 13, and is transported toward the peripheral edge portion of the lower steam flow path concave portion 12, thereby suppressing the flow of the steam from being obstructed. The lower flow path wall 13 is arranged to overlap a corresponding upper flow path wall 22 (described later) of the upper metal sheet 20 in a plan view, thereby improving the mechanical strength of the steam chamber 1. The width w0 of the lower flow path wall portion 13 is, for example, 0.1mm to 30mm, preferably 0.1mm to 2.0mm, and the interval d between the lower flow path wall portions 13 adjacent to each other is 0.1mm to 30mm, preferably 0.1mm to 2.0 mm. Here, the width w0 is a dimension of the lower flow passage wall portion 13 in the 2 nd direction Y orthogonal to the 1 st direction X of the lower flow passage wall portion 13, and corresponds to a dimension in the vertical direction in fig. 4, for example. The height h0 (see fig. 3) of the lower flow path wall 13 (in other words, the depth of the lower steam flow path concave portion 12) is preferably smaller than the thickness T1 of the lower metal piece 10, which will be described later, by 10 μm or more. In this case, the difference between the thickness T1 and the height h0, that is, the thickness of the metal material of the lower metal piece 10 in the portion where the lower steam flow path concave portion 12 is formed, can be set to 10 μm or more. Therefore, the strength of the portion can be ensured, and the portion can be prevented from being deformed to be recessed inward with respect to the pressure received from the outside air. Such a height h0 may be 10 μm to 300. mu.m. For example, when the thickness T0 of the steam chamber 1 is 0.5mm and the thickness T1 of the lower metal piece 10 is equal to the thickness T2 of the upper metal piece 20, the height h0 can be set to 200 μm.

As shown in fig. 3 and 4, a lower peripheral wall 14 is provided at a peripheral edge of the lower metal sheet 10. The lower peripheral wall 14 is formed to surround the sealed space 3, particularly the lower steam flow path concave portion 12, and defines the sealed space 3. In addition, lower alignment holes 15 for positioning the lower metal piece 10 and the upper metal piece 20 are provided at four corners of the lower peripheral wall 14 in a plan view.

In the present embodiment, the upper metal sheet 20 has substantially the same structure as the lower metal sheet 10, except that a liquid flow path portion 30 described later is not provided. The structure of the upper metal sheet 20 will be described in more detail below.

As shown in fig. 3 and 5, the upper metal sheet 20 has an upper steam flow path concave portion 21 (2 nd steam flow path concave portion) provided on the lower surface 20 a. The upper steam flow path concave portion 21 constitutes a part of the sealed space 3, and is mainly configured to diffuse and cool the steam generated by the evaporation portion 11. More specifically, the steam in the upper steam flow path concave portion 21 diffuses in a direction away from the evaporation portion 11, and most of the steam is sent to the peripheral edge portion having a relatively low temperature. As shown in fig. 3, a case member Ha constituting a part of a case H (see fig. 1) of a mobile terminal or the like is disposed on the upper surface 20b of the upper metal piece 20. Thereby, the steam in the upper steam flow path concave portion 21 is cooled outside through the upper metal sheet 20 and the housing member Ha.

In the present embodiment, as shown in fig. 2, 3, and 5, a plurality of upper flow path wall portions 22 (No. 2 flow path wall portions) protruding downward (in a direction perpendicular to the bottom surface 21 a) from the bottom surface 21a of the upper steam flow path recess portion 21 are provided in the upper steam flow path recess portion 21 of the upper metal sheet 20. In the present embodiment, an example is shown in which the upper flow path wall portion 22 extends in an elongated shape along the 1 st direction X (the left-right direction in fig. 5) of the steam chamber 1. The upper flow path wall portion 22 includes a flat lower surface 22a (the 2 nd contact surface, the projecting end surface) that is in contact with the upper surface 10a of the lower metal sheet 10 (more specifically, the upper surface 13a of the lower flow path wall portion 13) and covers the liquid flow path portion 30. The upper flow path wall portions 22 are arranged in parallel with each other at equal intervals. Thus, the steam of the working fluid 2 flows around each of the upper flow path wall portions 22, and the steam is sent to the peripheral edge portion of the upper steam flow path concave portion 21, thereby preventing the steam from being hindered from flowing. The upper flow path wall 22 is disposed so as to overlap the corresponding lower flow path wall 13 of the lower metal sheet 10 in a plan view, thereby improving the mechanical strength of the steam chamber 1. The width and height of the upper flow path wall portion 22 are preferably the same as the width w0 and height h0 of the lower flow path wall portion 13 described above. Here, the bottom surface 21a of the upper steam flow path concave portion 21 may be a top surface in the vertical arrangement relationship between the lower metal piece 10 and the upper metal piece 20 as shown in fig. 3 and the like, but is described as the bottom surface 21a in the specification so as to correspond to the surface on the back side of the upper steam flow path concave portion 21.

As shown in fig. 3 and 5, an upper peripheral wall 23 is provided at the peripheral edge of the upper metal piece 20. The upper peripheral wall 23 is formed to surround the sealed space 3, particularly the upper steam flow path recessed portion 21, and defines the sealed space 3. In addition, in a plan view, upper alignment holes 24 for positioning the lower metal piece 10 and the upper metal piece 20 are provided at four corners of the upper peripheral wall 23. That is, each upper alignment hole 24 is constituted by: the positioning holes are arranged to overlap the respective lower alignment holes 15 in the temporary fixing described later, and the lower metal piece 10 and the upper metal piece 20 can be positioned.

Such a lower metal sheet 10 and an upper metal sheet 20 are preferably permanently bonded to each other by diffusion bonding. More specifically, as shown in fig. 3, the upper surface 14a of the lower peripheral wall 14 of the lower metal piece 10 abuts against the lower surface 23a of the upper peripheral wall 23 of the upper metal piece 20, and the lower peripheral wall 14 and the upper peripheral wall 23 are joined to each other. Thereby, a sealed space 3 for sealing the working fluid 2 is formed between the lower metal piece 10 and the upper metal piece 20. Further, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 is in contact with the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20, and each lower flow path wall portion 13 and the corresponding upper flow path wall portion 22 are joined to each other. Thereby, the mechanical strength of the steam chamber 1 is improved. In particular, since the lower flow path wall portion 13 and the upper flow path wall portion 22 of the present embodiment are arranged at equal intervals, the mechanical strength at each position of the steam chamber 1 can be equalized. The lower metal sheet 10 and the upper metal sheet 20 may be joined by other means such as brazing as long as they can be permanently joined without diffusion bonding.

As shown in fig. 2, the steam chamber 1 further includes an injection portion 4 for injecting the working fluid 2 into the sealed space 3 at one of the pair of ends in the 1 st direction X. Injection portion 4 has a lower injection protrusion 16 protruding from an end surface of lower metal sheet 10 and an upper injection protrusion 25 protruding from an end surface of upper metal sheet 20. Among them, a lower injection flow path concave portion 17 is formed on the upper surface of the lower injection protrusion 16, and an upper injection flow path concave portion 26 is formed on the lower surface of the upper injection protrusion 25. The lower injection flow path concave portion 17 communicates with the lower steam flow path concave portion 12, and the upper injection flow path concave portion 26 communicates with the upper steam flow path concave portion 21. The lower injection flow path concave portion 17 and the upper injection flow path concave portion 26 form an injection flow path of the working fluid 2 when the lower metal sheet 10 and the upper metal sheet 20 are joined. The working fluid 2 is injected into the sealed space 3 through the injection flow path. In the present embodiment, the example in which the injection portion 4 is provided at one end of the pair of ends of the steam chamber 1 in the 1 st direction X is shown, but the present invention is not limited to this.

Next, the liquid flow path portion 30 of the lower metal sheet 10 will be described in more detail with reference to fig. 3, 4, 6, and 7.

As shown in fig. 3 and 4, a liquid channel portion 30 through which the liquid working liquid 2 passes is provided on the upper surface 10a of the lower metal sheet 10 (more specifically, the upper surface 13a of each lower channel wall portion 13). The liquid flow path portion 30 constitutes a part of the sealed space 3, and communicates with the lower steam flow path concave portion 12 and the upper steam flow path concave portion 21.

As shown in fig. 6, the liquid channel portion 30 includes a 1 st main flow channel 31, a 2 nd main flow channel 32, a 3 rd main flow channel 33, and a 4 th main flow channel 34. The 1 st to 4 th main flow grooves 31 to 34 linearly extend in the 1 st direction X and pass through the liquid working fluid 2, and are sequentially arranged in the 2 nd direction Y. That is, the 4 th main flow groove 34 is disposed on the opposite side of the 2 nd main flow groove 32 side from the 3 rd main flow groove 33. The 1 st to 4 th main flow grooves 31 to 34 are mainly configured to convey the working fluid 2 condensed from the steam generated by the evaporation unit 11 to the evaporation unit 11.

A 1 st projection row 41 is provided between the 1 st main flow groove 31 and the 2 nd main flow groove 32. The 1 st projection row 41 includes a plurality of 1 st projections 41a arranged in the 1 st direction X. In fig. 6, each 1 st projection 41a is formed in a rectangular shape in a plan view such that the 1 st direction X is a longitudinal direction. The 1 st communication groove 51 is interposed between the 1 st convex portions 41a adjacent to each other. The 1 st communication groove 51 is formed to extend in the 2 nd direction Y, and communicates the 1 st main flow groove 31 with the 2 nd main flow groove 32, so that the working fluid 2 can flow between the 1 st main flow groove 31 and the 2 nd main flow groove 32. The 1 st communication groove 51 is a region between the 1 st protruding portions 41a adjacent to each other, and is a region between the 1 st main flow groove 31 and the 2 nd main flow groove 32.

A 2 nd protrusion row 42 is provided between the 2 nd main flow groove 32 and the 3 rd main flow groove 33. The 2 nd projection row 42 includes a plurality of 2 nd projections 42a arranged in the 1 st direction X. In fig. 6, each 2 nd convex portion 42a is formed in a rectangular shape in a plan view such that the 1 st direction X becomes the longitudinal direction. The 2 nd communication groove 52 is interposed between the 2 nd convex portions 42a adjacent to each other. The 2 nd communication groove 52 is formed to extend in the 2 nd direction Y, and communicates the 2 nd main flow groove 32 with the 3 rd main flow groove 33, and the working fluid 2 can flow between the 2 nd main flow groove 32 and the 3 rd main flow groove 33. The 2 nd communication groove 52 is a region between the 2 nd convex portions 42a adjacent to each other, and is a region between the 2 nd main flow groove 32 and the 3 rd main flow groove 33.

The 2 nd main flow groove 32 includes a 1 st intersection P1 communicating with the 1 st communication groove 51 and a 2 nd intersection P2 communicating with the 2 nd communication groove 52.

In the 1 st intersection portion P1, at least a part of the 1 st communication groove 51 faces the 2 nd convex portion 42 a. As shown in fig. 6, in the 1 st intersection P1, the entire 1 st communication groove 51 (the entire region in the width direction (1 st direction X) of the 1 st communication groove 51) faces the 2 nd convex portion 42 a. Thus, the side wall 36 (wall of the 2 nd convex portion 42 a) on the opposite side to the 1 st communication groove 51 side, of the pair of

side walls

35, 36 along the 1 st direction X of the 2 nd main flow groove 32, is arranged over the entire 1 st intersection portion P1. In the embodiment shown in fig. 6, the 1 st communication groove 51 is arranged to overlap the center of the 2 nd convex portion 42a in the 1 st direction X as viewed in the 2 nd direction Y. In this way, in the 1 st intersection P1, the 2 nd main flow groove 32 and the 1 st communication groove 51 intersect in a T shape. The 1 st intersection P1 is a region between the main runner trunk portions 31a to 34a adjacent to each other in the 1 st direction X, and is a region between the communication grooves 51 to 54 and the convex portions 41a to 44a adjacent to each other in the 2 nd direction Y. In other words, the main grooves 31 to 34 are regions where they intersect the communication grooves 51 to 54 (i.e., regions where they overlap). Here, the 1 st main flow channel bodies 31a to 34a constitute parts of the 1 st to 4 th main flow channels 31 to 34, are provided between the 1 st intersection P1 and the 2 nd intersection P2, and are positioned between the adjacent convex portions 41a to 44 a.

Similarly, in the 2 nd intersection portion P2, at least a part of the 2 nd communication groove 52 faces the 1 st projection 41 a. As shown in fig. 6, in the 2 nd intersection portion P2, the entire 2 nd communication groove 52 (the entire region in the width direction (1 st direction X) of the 2 nd communication groove 52) faces the 1 st protruding portion 41 a. Thus, the side wall 35 (the wall of the 1 st protruding portion 41 a) on the opposite side to the 2 nd communication groove 52 side, of the pair of

side walls

35, 36 along the 1 st direction X of the 2 nd main flow groove 32, is arranged over the entire 2 nd intersection portion P2. In the embodiment shown in fig. 6, the 2 nd communication groove 52 is arranged to overlap the center of the 1 st convex portion 41a in the 1 st direction X when viewed in the 2 nd direction Y. In this way, in the 2 nd intersection P2, the 2 nd main flow groove 32 and the 2 nd communication groove 52 intersect in a T shape. The 2 nd intersection portion P2 is a region between the main flow channel main bodies 31a to 34a adjacent to each other in the 1 st direction X, and is a region between the communication grooves 51 to 54 and the convex portions 41a to 44a adjacent to each other in the 2 nd direction Y. In other words, the main grooves 31 to 34 are regions where they intersect the communication grooves 51 to 54 (i.e., regions where they overlap).

As described above, in the 1 st intersection P1 of the 2 nd main flow channel 32, the 1 st communication groove 51 faces the 2 nd convex portion 42a, and in the 2 nd intersection P2 of the 2 nd main flow channel 32, the 2 nd communication groove 52 faces the 1 st convex portion 41 a. Thus, the 1 st communication groove 51 and the 2 nd communication groove 52 are not arranged on a straight line. That is, the 1 st communication groove 51 communicating with the 2 nd main flow groove 32 on one side and the 2 nd communication groove 52 communicating with the other side are not arranged on a straight line.

In the present embodiment, the 1 st projection 41a and the 2 nd projection 42a have the same shape, and the arrangement pitch of the 1 st projection 41a is the same as the arrangement pitch of the 2 nd projection 42 a. The 1 st projection 41a and the 2 nd projection 42a are arranged to be shifted from each other in the 1 st direction X by a dimension of half of the arrangement pitch.

In addition, in the present embodiment, the 1 st intersection P1 and the 2 nd intersection P2 of the 2 nd main flow channel 32 are adjacent to each other. That is, no other intersection portion (for example, 3 rd intersection portion P3 shown in fig. 14 described later) is interposed between 1 st intersection portion P1 and 2 nd intersection portion P2. The 2 nd main flow channel 32 includes a plurality of 1 st intersections P1 and a plurality of 2 nd intersections P2, and the 1 st intersections P1 and the 2 nd intersections P2 are alternately arranged in the 1 st direction X. That is, the pair of

side walls

35 and 36 of the 2 nd main flow channel 32 are intermittently formed, and the open positions of the

side walls

35 and 36 are shifted from each other in the 1 st direction X.

However, a 3 rd projection row 43 is provided between the 3 rd main flow groove 33 and the 4 th main flow groove 34. The 3 rd projection row 43 includes a plurality of 3 rd projections 43a arranged in the 1 st direction X, similarly to the 1 st projection row 41. The 3 rd communication groove 53 is interposed between the 3 rd convex portions 43a adjacent to each other. The 3 rd communication groove 53 is formed to extend in the 2 nd direction Y, and communicates the 3 rd main flow groove 33 with the 4 th main flow groove 34, so that the working fluid 2 can flow between the 3 rd main flow groove 33 and the 4 th main flow groove 34. The 3 rd communication groove 53 is a region between the 3 rd protruding portions 43a adjacent to each other, and is a region between the 3 rd main flow groove 33 and the 4 th main flow groove 34.

The 3 rd main flow groove 33 includes a 1 st intersection P1 communicating with the 2 nd communication groove 52 and a 2 nd intersection P2 communicating with the 3 rd communication groove 53. In the 1 st intersection portion P1, at least a part of the 2 nd communication groove 52 faces the 3 rd protruding portion 43 a. In fig. 6, in the 1 st intersection P1, the entire 2 nd communication groove 52 (the entire region in the width direction (1 st direction X) of the 2 nd communication groove 52) faces the 3 rd protruding portion 43 a. Accordingly, the side wall 36 (the wall of the 3 rd protruding portion 43 a) on the opposite side to the 2 nd communication groove 52 side among the pair of

side walls

35 and 36 along the 1 st direction X of the 3 rd main flow groove 33 exists over the entire 1 st intersection portion P1. In the embodiment shown in fig. 6, the 2 nd communication groove 52 is arranged to overlap the center of the 3 rd protruding portion 43a in the 1 st direction X when viewed in the 2 nd direction Y. In this way, in the 1 st intersection P1, the 3 rd main flow groove 33 and the 2 nd communication groove 52 intersect in a T shape.

Similarly, in the 2 nd intersection portion P2, at least a part of the 3 rd communication groove 53 faces the 2 nd convex portion 42 a. In fig. 6, in the 2 nd intersection P2, the entire 3 rd communication groove 53 (the entire region in the width direction (1 st direction X) of the 3 rd communication groove 53) faces the 2 nd convex portion 42 a. Thus, the side wall 35 (wall of the 2 nd convex portion 42 a) on the opposite side to the 3 rd communication groove 53 side, of the pair of

side walls

35, 36 along the 1 st direction X of the 3 rd main flow groove 33, is arranged over the entire 2 nd intersection portion P2. In the embodiment shown in fig. 6, the 3 rd communication groove 53 is arranged to overlap the center of the 2 nd convex portion 42a in the 1 st direction X when viewed in the 2 nd direction Y. In this way, in the 2 nd intersection P2, the 3 rd main flow groove 33 and the 3 rd communication groove 53 intersect in a T shape.

That is, in the present embodiment, the 1 st, 2 nd, and 3 rd

convex portions

41a, 42a, and 43a have the same shape, and the arrangement pitch of the 1 st convex portions 41a, the arrangement pitch of the 2 nd convex portions 42a, and the arrangement pitch of the 3 rd convex portions 43a are the same. The 2 nd projection 42a and the 3 rd projection 43a are arranged to be shifted from each other in the 1 st direction X by a dimension of half of the arrangement pitch. As a result, the 1 st projection 41a and the 3 rd projection 43a are arranged at the same position in the 1 st direction X, and the 1 st projection 41a and the 3 rd projection 43a overlap each other when viewed in the 2 nd direction Y.

In the present embodiment, like the 2 nd main flow channel 32, the 1 st intersection P1 and the 2 nd intersection P2 of the 3 rd main flow channel 33 are adjacent to each other. The 3 rd main flow channel 33 includes a plurality of 1 st intersections P1 and a plurality of 2 nd intersections P2, and the 1 st intersections P1 and the 2 nd intersections P2 are alternately arranged in the 1 st direction X. That is, the pair of

side walls

35 and 36 of the 3 rd main flow channel 33 are intermittently formed, and the open positions of the

side walls

35 and 36 are shifted from each other in the 1 st direction X.

As described above, since the 1 st, 2 nd, and 3 rd

convex portions

41a, 42a, and 43a are arranged, in the present embodiment, the 1 st, 2 nd, and 3 rd

convex portions

41a, 42a, and 43a are arranged in a zigzag shape. As a result, the 1 st, 2 nd, and 3

rd communication grooves

51, 52, and 53 are also arranged in a zigzag shape.

Fig. 6 shows a set of main ducts for the set of 1 st to 4 th main ducts 31 to 34. The plurality of main flow grooves 31 to 34 may be provided in this group, and the entire main flow groove may be formed in the upper surface 13a of the lower flow passage wall 13. The number of main flow grooves constituting the liquid flow path portion 30 is not limited to a multiple of 4, and is arbitrary as long as at least three main flow grooves are formed, without the need to form the 1 st to 4 th main flow grooves 31 to 34 as a set.

In this case, the 1 st main flow groove 31 described above is provided on the opposite side of the 4 th main flow groove 34 from the 3 rd main flow groove 33 side, and the 4 th protrusion row 44 is provided between the 4 th main flow groove 34 and the 1 st main flow groove 31. The 4 th projection row 44 includes a plurality of 4 th projections 44a arranged in the 1 st direction X, similarly to the 2 nd projection row 42 described above. The 4 th convex portion 44a and the 2 nd convex portion 42a are arranged at the same position in the 1 st direction X, and the 4 th convex portion 44a and the 2 nd convex portion 42a overlap when viewed in the 2 nd direction Y. The 4 th communication groove 54 is interposed between the 4 th convex portions 44a adjacent to each other. The 4 th communication groove 54 is formed to extend in the 2 nd direction Y, and communicates the 4 th main flow groove 34 with the 1 st main flow groove 31, so that the working fluid 2 can flow between the 4 th main flow groove 34 and the 1 st main flow groove 31. The 4 th communication groove 54 is a region between the 4 th protruding portions 44a adjacent to each other, and is a region between the 4 th main flow groove 34 and the 1 st main flow groove 31.

The 4 th main flow channel 34 has the 1 st intersection P1 and the 2 nd intersection P2 similar to the 2 nd main flow channel 32. Here, in the 1 st intersection P1, the 3 rd communication groove 53 communicates with the 4 th main flow groove 34, and in the 2 nd intersection P2, the 4 th communication groove 54 communicates with the 4 th main flow groove 34. Further, the 1 st main flow channel 31 has the 1 st intersection P1 and the 2 nd intersection P2 similar to the 3 rd main flow channel 33. Here, in the 1 st intersection P1, the 4 th communication groove 54 communicates with the 1 st main flow groove 31, and in the 2 nd intersection P2, the 1 st communication groove 51 communicates with the 1 st main flow groove 31. The 1 st intersection P1 and the 2 nd intersection P2 in the 1 st main flow channel 31 and the 4 th main flow channel 34 are the same as the 1 st intersection P1 and the 2 nd intersection P2 in the 2 nd main flow channel 32 and the 3 rd main flow channel 33, and therefore, detailed description thereof is omitted.

The respective convex portions 41a to 44a may be arranged in a zigzag shape in a rectangular shape over the entire liquid channel portion 30 as described above.

However, the width w1 (dimension in the 2 nd direction Y) of the 1 st to 4 th main flow grooves 31 to 34 is preferably larger than the width w2 (dimension in the 2 nd direction Y) of the 1 st to 4 th protrusions 41a to 44 a. In this case, the ratio of the 1 st to 4 th main flow grooves 31 to 34 to the upper surface 13a of the lower flow passage wall 13 can be increased. Therefore, the flow channel density of the main flow channels 31 to 34 on the upper surface 13a can be increased, and the function of conveying the liquid working fluid 2 can be improved. For example, the width w1 of the 1 st to 4 th main flow grooves 31 to 34 may be 30 μm to 200 μm, and the width w2 of the 1 st to 4 th protrusions 41a to 44a may be 20 μm to 180 μm.

The depth h1 of the 1 st to 4 th main flow grooves 31 to 34 is preferably smaller than the depth h0 of the lower steam flow path recessed portion 12. In this case, the capillary action of the 1 st to 4 th main flow grooves 31 to 34 can be improved. For example, the depth h1 of the 1 st to 4 th main flow grooves 31 to 34 is preferably about half of h0, and may be 5 μm to 180 μm.

Further, the width w3 (dimension in the 1 st direction X) of the 1 st to 4 th communication grooves 51 to 54 is preferably smaller than the width w1 of the 1 st to 4 th main flow grooves 31 to 34. In this case, while the liquid working fluid 2 is being transported toward the evaporation portion 11 in each of the main flow grooves 31 to 34, the working fluid 2 can be prevented from flowing into the communication grooves 51 to 54, and the transport function of the working fluid 2 can be improved. On the other hand, when dry-up occurs in any one of the main flow channels 31 to 34, the working fluid 2 can be moved from the adjacent main flow channels 31 to 34 through the corresponding communication channels 51 to 54, and dry-up can be quickly eliminated, thereby ensuring the function of conveying the working fluid 2. That is, as long as the 1 st to 4 th communication grooves 51 to 54 can communicate the adjacent main flow grooves 31 to 34 with each other, the function thereof can be exhibited even if the width w1 of the main flow grooves 31 to 34 is smaller. The width w3 of the 1 st to 4 th communication grooves 51 to 54 may be, for example, 20 to 180 μm.

The depth h3 of the 1 st to 4 th communication grooves 51 to 54 may be shallower than the depth h1 of the 1 st to 4 th main flow grooves 31 to 34 according to the width w3 thereof. For example, the depth h3 (not shown) of the 1 st to 4 th communication grooves 51 to 54 may be 40 μm when the depth h1 of the 1 st to 4 th main flow grooves 31 to 34 is 50 μm.

Here, the method for confirming the width and depth of the main flow grooves 31 to 34 and the width and depth of the communication grooves 51 to 54 from the completed steam chamber 1 will be described later.

The cross-sectional shape (cross-sectional shape in the 2 nd direction Y) of the 1 st to 4 th main runners 31 to 34 is not particularly limited, and may be, for example, rectangular, curved, semicircular, or V-shaped. The 1 st to 4 th communication grooves 51 to 54 have the same cross-sectional shape (cross-section in the 1 st direction X). Fig. 7 shows an example in which the 1 st to 4 th main flow grooves 31 to 34 are formed in a rectangular shape in cross section.

However, the liquid flow path portion 30 is formed on the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10. On the other hand, in the present embodiment, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is formed in a flat shape. Thus, the main flow grooves 31 to 34 of the liquid flow path section 30 are covered with the flat lower surface 22 a. In this case, as shown in fig. 7, the pair of

side walls

35 and 36 extending in the 1 st direction X of the main flow channels 31 to 34 and the lower surface 22a of the upper flow channel wall 22 can form two right-angled or acute-angled corners 37, and the capillary action of the two corners 37 can be improved. That is, the two corners 38 can be formed by the bottom surfaces (the surfaces on the lower surface 10b side of the lower metal sheet 10) of the main flow grooves 31 to 34 and the pair of

side walls

35 and 36 of the main flow grooves 31 to 34, but when the main flow grooves 31 to 34 are formed by etching as described later, the corners 38 on the bottom surfaces tend to be rounded. Therefore, the lower surface 22a of the upper flow path wall 22 is formed flat so as to cover the main flow paths 31 to 34 and the communication paths 51 to 54, whereby the capillary action can be improved at the corner 37 on the lower surface 22a side of the upper flow path wall 22. In fig. 7, for the sake of clarity of the drawing, only the

side walls

35 and 36 and the

corners

37 and 38 of the 1 st main runner 31 are shown, and the

side walls

35 and 36 and the

corners

37 and 38 of the 2 nd to 4 th main runners 32 to 34 are omitted.

The material for the lower metal sheet 10 and the upper metal sheet 20 is not particularly limited as long as it has good thermal conductivity, and for example, the lower metal sheet 10 and the upper metal sheet 20 are preferably formed of copper (oxygen-free copper) or a copper alloy. This can improve the thermal conductivity of the lower metal piece 10 and the upper metal piece 20. Therefore, the heat dissipation efficiency of the steam chamber 1 can be improved. Alternatively, if the desired heat dissipation efficiency can be obtained, other metal materials such as aluminum and other metal alloy materials such as stainless steel can be used for the

metal sheets

10 and 20.

Next, the operation of the present embodiment configured as described above will be described. Here, first, a method for manufacturing the vapor chamber 1 will be described with reference to fig. 8 to 13, but the description of the half-etching step of the upper metal sheet 20 is simplified. Fig. 8 to 13 show the same cross-section as the cross-section of fig. 3.

First, as shown in fig. 8, a flat plate-like metal material sheet M is prepared as a preparation step.

Next, as shown in fig. 9, the metal material sheet M is half-etched to form the lower vapor flow path concave portion 12 constituting a part of the sealed space 3. In this case, first, a 1 st resist film, not shown, is formed on the upper surface Ma of the metal material sheet M in a pattern corresponding to the plurality of lower flow path wall portions 13 and the lower peripheral wall 14 by a photolithography technique. Next, as a 1 st half etching step, the upper surface Ma of the metal material sheet M is half etched. Thus, the portions of the upper surface Ma of the metal material sheet M corresponding to the resist openings (not shown) of the 1 st resist film are half-etched to form the lower vapor flow path concave portions 12, the lower flow path wall portions 13, and the lower peripheral wall portions 14 as shown in fig. 9. At this time, the lower injection flow path concave portion 17 shown in fig. 2 and 4 is also formed at the same time, and the metal material piece M is etched from the upper surface Ma and the lower surface so as to have the outer contour shape as shown in fig. 4, thereby obtaining a predetermined outer contour shape. After the 1 st half etching process, the 1 st resist film is removed. The half etching is etching for forming a concave portion that does not penetrate through a material. Therefore, the depth of the recess formed by half etching is not limited to half the thickness of the lower metal sheet 10. As the etching solution, for example, an iron chloride-based etching solution such as an aqueous solution of ferric chloride or a copper chloride-based etching solution such as an aqueous solution of copper chloride can be used.

After the lower steam flow path recessed portion 12 is formed, as shown in fig. 10, a liquid flow path portion 30 is formed on the upper surface 13a of the lower flow path wall portion 13.

In this case, first, a 2 nd resist film, not shown, is formed on the upper surface 13a of the lower flow path wall portion 13 in a pattern corresponding to the 1 st to 4 th convex portions 41a to 44a of the liquid flow path portion 30 by photolithography. Next, as a 2 nd half-etching step, the upper surface 13a of the lower flow path wall portion 13 is half-etched. Thus, a portion of the upper surface 13a corresponding to the resist opening (not shown) of the 2 nd resist film is half-etched, and the liquid channel portion 30 is formed on the upper surface 13a of the lower channel wall portion 13. That is, the respective convex portions 41a to 44a are formed on the upper surface 13 a. The convex portions 41a to 44a define the 1 st to 4 th main flow grooves 31 to 34 and the 1 st to 4 th communication grooves 51 to 54. After the 2 nd half etching process, the 2 nd resist film is removed.

Thus, the lower metal sheet 10 having the liquid channel portion 30 formed therein is obtained. In addition, the main grooves 31 to 34 and the communication grooves 51 to 54 can be easily formed at a depth different from the depth h0 of the lower steam flow path concave portion 12 by forming the liquid flow path portion 30 as the 2 nd half etching step which is a step different from the 1 st half etching step. However, the lower steam flow path concave portion 12, the main flow grooves 31 to 34, and the communication grooves 51 to 54 may be formed in the same half etching process. In this case, the number of half-etching steps can be reduced, and the manufacturing cost of the vapor chamber 1 can be reduced.

On the other hand, similarly to the lower metal sheet 10, the upper metal sheet 20 is half-etched from the lower surface 20a to form an upper steam flow path concave portion 21, an upper flow path wall portion 22, and an upper peripheral wall 23. Thus, the upper metal piece 20 is obtained.

Next, as shown in fig. 11, as a provisional fixing step, the lower metal piece 10 having the lower steam flow path recessed portion 12 and the upper metal piece 20 having the upper steam flow path recessed portion 21 are provisionally fixed. In this case, first, the lower metal piece 10 and the upper metal piece 20 are positioned by the lower alignment hole 15 (see fig. 2 and 4) of the lower metal piece 10 and the upper alignment hole 24 (see fig. 2 and 5) of the upper metal piece 20. Next, the lower metal piece 10 and the upper metal piece 20 are fixed. The fixing method is not particularly limited, and for example, the lower metal piece 10 and the upper metal piece 20 may be fixed by resistance welding the lower metal piece 10 and the upper metal piece 20. In this case, as shown in fig. 11, it is preferable to perform spot resistance welding using the electrode rod 40. Laser welding may be performed instead of resistance welding. Alternatively, the lower metal sheet 10 and the upper metal sheet 20 may be fixed by ultrasonic bonding by irradiating ultrasonic waves. Further, an adhesive may be used, but an adhesive having no organic component or a small amount of organic component is preferably used. Thus, the lower metal piece 10 and the upper metal piece 20 are fixed in a positioned state.

After the temporary fixing, as shown in fig. 12, as a permanent joining step, the lower metal sheet 10 and the upper metal sheet 20 are permanently joined by diffusion bonding. The diffusion bonding is a method in which the lower metal sheet 10 and the upper metal sheet 20 to be bonded are brought into close contact with each other, and the

metal sheets

10 and 20 are heated while being pressurized in a direction in which they are brought into close contact with each other in a controlled atmosphere such as vacuum or inert gas, thereby bonding by diffusion of atoms generated at the bonding surface. The diffusion bonding heats the materials of the lower metal sheet 10 and the upper metal sheet 20 to a temperature close to the melting point, but since the temperature is lower than the melting point, the

metal sheets

10 and 20 can be prevented from being melted and deformed. More specifically, the upper surface 14a of the lower peripheral wall 14 of the lower metal piece 10 and the lower surface 23a of the upper peripheral wall 23 of the upper metal piece 20 are diffusion bonded together as a bonding surface. Thus, the lower peripheral wall 14 and the upper peripheral wall 23 form the sealed space 3 between the lower metal piece 10 and the upper metal piece 20. Further, an injection flow path for the working fluid 2 communicating with the sealed space 3 is formed by the lower injection flow path recessed portion 17 (see fig. 2 and 4) and the upper injection flow path recessed portion 26 (see fig. 2 and 5). Further, the upper surface 13a of the lower flow path wall portion 13 of the lower metal sheet 10 and the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 are diffusion bonded as a bonding surface, and the mechanical strength of the steam chamber 1 is improved. The liquid flow path portion 30 formed on the upper surface 13a of the lower flow path wall portion 13 remains as a flow path for the liquid working fluid 2.

After the permanent joining, as shown in fig. 13, the working fluid 2 is injected into the sealed space 3 from the injection portion 4 (see fig. 2) as an enclosing step. At this time, first, the sealed space 3 is evacuated and depressurized, and then the working fluid 2 is injected into the sealed space 3. During injection, the working fluid 2 passes through an injection flow path formed by the lower injection flow path concave portion 17 and the upper injection flow path concave portion 26. For example, the sealing amount of the working fluid 2 is also based on the configuration of the fluid channel portion 30 inside the steam chamber 1, but may be 10 to 30% with respect to the total volume of the sealed space 3.

After the working fluid 2 is injected, the injection flow path is sealed. For example, the injection portion 4 may be irradiated with laser light to partially melt the injection portion 4 and seal the injection flow path. Thereby, the communication between the sealed space 3 and the outside is blocked, and the working fluid 2 is sealed in the sealed space 3. This prevents the working fluid 2 in the sealed space 3 from leaking to the outside. For sealing, the injection portion 4 may be riveted or brazed.

As described above, the steam chamber 1 of the present embodiment is obtained.

Next, an operation method of the vapor chamber 1, that is, a cooling method of the device D will be described.

The steam chamber 1 obtained as described above is provided in a housing H such as a mobile terminal, and a device D such as a CPU as an object to be cooled is mounted on the lower surface 10b of the lower metal sheet 10. Since the amount of the working fluid 2 injected into the sealed space 3 is small, the liquid working fluid 2 in the sealed space 3 adheres to the wall surface of the sealed space 3, that is, the wall surface of the lower steam flow path concave portion 12, the wall surface of the upper steam flow path concave portion 21, and the wall surface of the liquid flow path portion 30, due to the surface tension thereof.

When the device D generates heat in this state, the working fluid 2 in the lower vapor flow path concave portion 12 and existing in the evaporation portion 11 is heated from the device D. The received heat is absorbed as latent heat, and the working fluid 2 is evaporated (vaporized), thereby generating vapor of the working fluid 2. Most of the generated steam diffuses in the lower steam flow path concave portion 12 and the upper steam flow path concave portion 21 constituting the sealed space 3 (see solid arrows in fig. 4). The steam in the upper steam flow path concave portion 21 and the lower steam flow path concave portion 12 is separated from the evaporation portion 11, and most of the steam is sent to the peripheral portion of the steam chamber 1 having a relatively low temperature. The diffused steam is cooled by radiating heat to the lower metal piece 10 and the upper metal piece 20. The heat received by the lower metal piece 10 and the upper metal piece 20 from the steam is transmitted to the outside through the case member Ha (see fig. 3).

The steam is condensed by losing latent heat absorbed in the evaporation portion 11 by radiating heat to the lower metal sheet 10 and the upper metal sheet 20. The working fluid 2 condensed into a liquid state adheres to the wall surface of the lower vapor flow path concave portion 12 or the wall surface of the upper vapor flow path concave portion 21. Here, since the working fluid 2 continues to evaporate in the evaporation unit 11, the working fluid 2 in the portion other than the evaporation unit 11 in the fluid flow path unit 30 is transported toward the evaporation unit 11 (see a dotted arrow in fig. 4). Thereby, the liquid working fluid 2 adhering to the wall surface of the lower vapor flow path concave portion 12 and the wall surface of the upper vapor flow path concave portion 21 moves toward the liquid flow path portion 30 and enters the liquid flow path portion 30. That is, the working fluid 2 in a liquid state is filled into the main flow grooves 31 to 34 and the communication grooves 51 to 54 through the 1 st to 4 th communication grooves 51 to 54 into the 1 st to 4 th main flow grooves 31 to 34. Therefore, the filled working fluid 2 obtains a propulsive force toward the evaporation portion 11 by the capillary action of the main flow grooves 31 to 34, and is smoothly transported to the evaporation portion 11.

In the liquid flow path part 30, each main flow groove 31-34 is communicated with other adjacent main flow grooves 31-34 through corresponding communication grooves 51-54. This can prevent the liquid working fluid 2 from flowing between the main flow channels 31 to 34 adjacent to each other and causing the main flow channels 31 to 34 to dry up. Therefore, a capillary action is given to the working fluid 2 in each main flow channel 31 to 34, and the working fluid 2 is smoothly transported to the evaporation portion 11.

Further, since each of the main channels 31 to 34 includes the 1 st intersection P1 and the 2 nd intersection P2, the capillary action acting on the working fluid 2 in each of the main channels 31 to 34 can be prevented from being lost. Here, for example, when the 1 st and 2

nd communication grooves

51, 52 are arranged on a straight line across the 2 nd main flow groove 32, both the pair of

side walls

35, 36 do not exist at the intersection with the 2 nd main flow groove 32. In this case, the capillary action in the direction toward the evaporation portion 11 is lost at the intersection, and the propulsive force of the working fluid 2 toward the evaporation portion 11 can be reduced.

In contrast, in the present embodiment, as described above, the 1 st communication groove 51 communicating with the 2 nd main flow groove 32 on one side and the 2 nd communication groove 52 communicating with the other side are not arranged on a straight line. In this case, as shown in fig. 6, the side wall 36 on the opposite side from the 1 st communication groove 51 side among the pair of

side walls

35 and 36 extending in the 1 st direction X of the 2 nd main flow groove 32 is arranged at the 1 st intersection P1. This can prevent the capillary action in the direction toward the evaporation unit 11 from being lost at the 1 st intersection P1. Similarly, the side wall 35 opposite to the 2 nd communication groove 52 side is disposed in the 2 nd intersection P2, and therefore the capillary action in the direction toward the evaporation portion 11 can be prevented from being lost. Therefore, in the respective intersections P1, P2, a decrease in capillary action can be suppressed, and capillary action can be continuously imparted to the working fluid 2 heading toward the evaporation portion 11.

In the present embodiment, the 1 st intersection P1 and the 2 nd intersection P2 of the 2 nd main flow channel 32 are alternately arranged. That is, in the 1 st intersection P1 of the 2 nd main flow channel 32, the capillary action is imparted to the working fluid 2 in the 2 nd main flow channel 32 by the side wall 36 on the 2 nd communication channel 52 side, but in the 2 nd intersection P2, the capillary action is imparted to the working fluid 2 in the 2 nd main flow channel 32 by the side wall 35 on the 1 st communication channel 51 side opposite to the side wall 36. Therefore, the capillary action acting on the working fluid 2 in the 2 nd main flow channel 32 can be equalized in the width direction (2 nd direction Y).

In the present embodiment, the 1 st main flow channel 31, the 3 rd main flow channel 33, and the 4 th main flow channel 34 have the 1 st intersection P1 and the 2 nd intersection P2, respectively, which are the same as the 2 nd main flow channel 32. This can suppress a decrease in the capillary action given to the working fluid 2 in the 1 st to 4 th main channels 31 to 34.

The working fluid 2 reaching the evaporation portion 11 is heated again from the device D and evaporated. Thus, the working fluid 2 flows back into the vapor chamber 1 while repeating phase change, i.e., evaporation and condensation, and the heat of the device D is transferred and released. As a result, the device D is cooled.

However, in the present embodiment, as described above, in the 2 nd main flow channel 32, the 1 st communication channel 51 and the 2 nd connection channel 52 are not arranged in the same straight line. Therefore, depending on the posture of the mobile terminal provided with the steam chamber 1, there may be a case where the 2 nd direction Y is more along the gravity direction than the 1 st direction X. In such a posture, when the 1 st communication groove 51 and the 2 nd communication groove 52 are arranged in the same straight line, the working fluid 2 flows in the 2 nd direction Y side in the communication grooves 51 to 54 in consideration of the influence of gravity on a part of the working fluid 2 in the main flow grooves 31 to 34, and the working fluid 2 is biased to the side.

However, as in the present embodiment, when each of the main flow channels 31 to 34 includes the 1 st intersection P1 and the 2 nd intersection P2, the working fluid 2 can be suppressed from flowing linearly toward one side in the 2 nd direction Y. That is, the working fluid 2 can advance toward the evaporation portion 11 through the main flow grooves 31 to 34 while heading toward the 2 nd direction Y side, and the flow of the working fluid 2 to the evaporation portion 11 can be suppressed from becoming weak. Therefore, even in a posture in which gravity acts in a direction that hinders the function of transporting the liquid working fluid 2 in the posture of the steam chamber 1, the function of transporting the liquid working fluid 2 can be improved.

However, the inside of the sealed space 3 is decompressed as described above. Thereby, the lower metal piece 10 and the upper metal piece 20 receive pressure in a direction of sinking inward from the outside air. Here, when the 1 st communication groove 51 and the 2 nd communication groove 52 are arranged on a straight line across the 2 nd main flow groove 32, an intersection portion where the 2 nd main flow groove 32, the 1 st communication groove 51, and the 2 nd communication groove 52 intersect in a cross shape is formed. In this case, the lower metal piece 10 and the upper metal piece 20 may be formed as a groove inwardly recessed in the 2 nd direction Y orthogonal to the 1 st direction X, and the recess may cross the 2 nd main flow groove 32. In this case, the flow path cross-sectional area of the 2 nd main flow channel 32 becomes small, and the flow path resistance of the working fluid 2 may increase.

In contrast, in the present embodiment, the 1 st communication groove 51 faces the 2 nd convex portion 42a in the 1 st intersection P1 of the 2 nd main flow groove 32. Thus, even when the lower metal piece 10 and the upper metal piece 20 are recessed inward along the 1 st communication groove 51, the recessed portions can be prevented from crossing the 2 nd main flow groove 32. Therefore, the flow path cross-sectional area of the 2 nd main flow channel 32 can be ensured, and the flow of the working fluid 2 can be prevented from being hindered. For example, in a steam chamber for a portable terminal that requires thinness, although it is difficult to suppress deformation due to its thinness, when the steam chamber 1 of the present embodiment is applied to such a steam chamber for a portable terminal, deformation due to dishing can be effectively suppressed according to the present embodiment. For example, when the thickness (residual thickness) of the portions of the lower metal sheet 10 where the main grooves 31 to 34 and the communication grooves 51 to 54 are formed is about 50 μm to 150 μm, it is considered effective to arrange the 1 st to 4 th protruding portions 41a to 44a in a zigzag shape in order to suppress the dent deformation. In addition, in the case of using oxygen-free copper as a material having good thermal conductivity, it is difficult to suppress dishing due to a decrease in mechanical strength of the material, but even in the case of forming the steam chamber 1 of the present embodiment from oxygen-free copper, dishing can be effectively suppressed.

As described above, according to the present embodiment, since the side wall 36 on the opposite side to the 1 st communication groove 51 side among the pair of

side walls

35 and 36 of the 2 nd main flow groove 32 can be disposed in the 1 st intersection P1, even when the lower metal piece 10 and the upper metal piece 20 are dented inward along the 1 st communication groove 51 by the pressure of the outside air, the dented portions can be prevented from crossing the 2 nd main flow groove 32. Similarly, in the 2 nd intersection portion P2, since the side wall 35 on the opposite side to the 2 nd communication groove 52 side of the pair of

side walls

35 and 36 of the 2 nd main flow groove 32 can be disposed, even when the lower metal piece 10 and the upper metal piece 20 are dented along the 1 st communication groove 51 by the pressure of the outside air, the dented portion can be prevented from crossing the 2 nd main flow groove 32. Therefore, the flow path cross-sectional area of the 2 nd main flow channel 32 can be ensured, and the flow of the working fluid 2 can be prevented from being hindered. As a result, the function of transporting the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

Further, according to the present embodiment, the 2 nd main flow channel 32 of the liquid flow channel section 30 includes the 1 st intersection P1 where the 1 st communication groove 51 faces the 2 nd convex portion 42a, and the 2 nd intersection P2 where the 2 nd communication groove 52 faces the 1 st convex portion 41 a. Thus, the side wall 36 on the opposite side to the 1 st communication groove 51 side of the pair of

side walls

35 and 36 of the 2 nd main flow groove 32 can be disposed in the 1 st intersection P1, and the side wall 35 on the opposite side to the 2 nd communication groove 52 side can be disposed in the 2 nd intersection P2. Therefore, capillary action can be continuously imparted to the working fluid 2 heading to the evaporation portion 11. In addition, in the 1 st intersection P1 and the 2 nd intersection P2, the capillary action can be imparted to the working fluid 2 in the 2 nd main flow channel 32 by the

side walls

35 and 36 disposed on the opposite sides to each other, and therefore the capillary action imparted to the working fluid 2 in the 2 nd main flow channel 32 can be equalized in the 2 nd direction Y. As a result, the decrease in the propulsive force of the working fluid 2 toward the evaporation unit 11 at the intersections P1 and P2 can be suppressed, the function of transporting the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

Further, according to the present embodiment, the 1 st intersection P1 and the 2 nd intersection P2 of the 2 nd main flow channel 32 are adjacent to each other. This can equalize the capillary action acting on the working fluid 2 in the 2 nd main flow channel 32 in the width direction.

Further, according to the present embodiment, the plurality of 1 st intersections P1 and the plurality of 2 nd intersections P2 of the 2 nd main flow channel 32 are alternately arranged. This can further equalize the capillary action given to the working fluid 2 in the 2 nd main flow channel 32.

Further, according to the present embodiment, the liquid flow path portion 30 includes the 3 rd main flow groove 33, and the 3 rd main flow groove 33 includes the 1 st intersection P1 where the 2 nd communication groove 52 faces the 3 rd convex portion 43a, and the 2 nd intersection P2 where the 3 rd communication groove 53 faces the 2 nd convex portion 42 a. Thus, similarly to the above-described 2 nd main flow channel 32, even when the lower metal piece 10 and the upper metal piece 20 are dented inward by the pressure of the outside air, the dented portions can be prevented from crossing the 3 rd main flow channel 33. Further, the capillary action given to the working fluid 2 in the 3 rd main flow channel 33 can be equalized. Therefore, the flow passage cross-sectional area of the 3 rd main flow channel 33 can be ensured. In particular, in the present embodiment, since the 1 st main flow channel 31 and the 4 th main flow channel 34 also include the 1 st intersection P1 and the 2 nd intersection P2, the capillary action imparted to the working fluid 2 is equalized over the entire fluid channel 30, the cross-sectional flow area of each main flow channel 31 to 34 can be ensured, and the function of conveying the working fluid 2 can be further improved.

Further, according to the present embodiment, since the 1 st intersection P1 and the 2 nd intersection P2 of the 3 rd main flow channel 33 are adjacent to each other, it is possible to further suppress the capillary action from being unevenly provided. In particular, since the plurality of 1 st intersections P1 and the plurality of 2 nd intersections P2 of the 3 rd main flow channel 33 are alternately arranged, the capillary action given to the working fluid 2 in the 3 rd main flow channel 33 can be further equalized.

Further, according to the present embodiment, the lower surface 22a of the upper flow path wall 22 of the upper metal sheet 20, which is in contact with the upper surface 13a of the lower flow path wall 13, is flat, and covers the 2 nd main flow channel 32. Thus, two corners 37 (see fig. 7) having a right-angled or acute-angled shape can be formed in the cross-section of each of the main flow grooves 31 to 34 and the communication grooves 51 to 54, and the capillary action of the working fluid 2 acting on the inside of each of the main flow grooves 31 to 34 and the inside of each of the communication grooves 51 to 54 can be improved.

In addition, according to the present embodiment, the width w1 of the 1 st to 4 th main flow grooves 31 to 34 is larger than the width w2 of the 1 st to 4 th protrusions 41a to 44 a. This can increase the ratio of the 1 st to 4 th main flow grooves 31 to 34 to the upper surface 13a of the lower flow passage wall 13. Therefore, the function of transporting the liquid working fluid 2 can be improved.

Further, according to the present embodiment, the 1 st to 4 th communication grooves 51 to 54 have a width w3 smaller than the width w1 of the 1 st to 4 th main flow grooves 31 to 34. Thus, while the liquid working fluid 2 is being transported toward the evaporation portion 11 in each of the main flow grooves 31 to 34, the working fluid 2 can be prevented from flowing into the communication grooves 51 to 54, and the transport function of the working fluid 2 can be improved. On the other hand, when dry-up occurs in any one of the main flow channels 31 to 34, the working fluid 2 can be moved from the adjacent main flow channels 31 to 34 through the corresponding communication channels 51 to 54, and dry-up can be quickly eliminated, thereby ensuring the function of conveying the working fluid 2.

In the above-described embodiment, an example in which the entire 1 st communication groove 51 faces the 2 nd convex portion 42a at the 1 st intersection P1 of the 2 nd main flow groove 32 and the entire 2 nd communication groove 52 faces the 1 st convex portion 41a at the 2 nd intersection P2 is described. However, the present invention is not limited to this, and in the 1 st intersection P1, a part of the 1 st communication groove 51 (a partial region in the width direction (1 st direction X) of the 1 st communication groove 51) may be opposed to the 2 nd convex portion 42 a. In the 2 nd intersection portion P2, a part of the 2 nd communication groove 52 may face the 1 st convex portion 41 a. That is, when viewed in the 2 nd direction Y, the 1 st communicating groove 51 and the 2 nd communicating groove 52 may partially overlap each other as long as they do not entirely overlap each other (as long as the 1 st communicating groove 51 and the 2 nd communicating groove 52 are not arranged on a straight line). In this case, side wall 36 of main flow channel 2 may be disposed at a portion of 1 st intersection P1 in 1 st direction X, and side wall 35 of main flow channel 2 may be disposed at a portion of 2 nd intersection P2 in 1 st direction X. Therefore, the loss of the capillary action in the direction toward the evaporation portion 11 in the 1 st intersection portion P1 can be prevented. The same applies to the 1 st intersection P1 and the 2 nd intersection P2 of the 1 st main flow channel 31, the 3 rd main flow channel 33, and the 4 th main flow channel 34, respectively.

In the above-described embodiment, the example in which the 1 st to 4 th main flow grooves 31 to 34 include the 1 st intersection P1 and the 2 nd intersection P2, respectively, is described. However, the present invention is not limited to this, and at least one of main flow channels 31 to 34 in flow channel section 30 may include 1 st intersection P1 and 2 nd intersection P2.

For example, the liquid channel section 30 may have the structure shown in fig. 14. In the embodiment shown in fig. 14, the 2 nd main flow channel 32 and the 4 th main flow channel 34 include the 1 st intersection P1 and the 2 nd intersection P2, as in the embodiment shown in fig. 6. However, the 1 st main flow channel 31 and the 3 rd main flow channel 33 do not include the 1 st intersection P1 and the 2 nd intersection P2 as in the embodiment shown in fig. 6. That is, in the 1 st main flow channel 31, the 4 th communication channel 54 and the 1 st communication channel 51 extending in the 2 nd direction Y are arranged on a straight line, and a 3 rd intersection P3 where the 1 st main flow channel 31, the 4 th communication channel 54, and the 1 st communication channel 51 intersect in a cross shape is formed. Similarly, in the 3 rd main flow channel 33, the 2 nd communication channel 52 and the 3 rd communication channel 53 extending in the 2 nd direction Y are also arranged on a straight line, and a 3 rd intersection P3 where the 3 rd main flow channel 33, the 2 nd communication channel 52, and the 3 rd communication channel 53 intersect in a cross shape is formed. Even in this manner, the function of conveying the liquid working fluid 2 in the fluid channel section 30 can be improved by providing the 1 st intersection P1 and the 2 nd intersection P2 in the 2 nd main channel 32 and the 4 th main channel 34.

In the above-described embodiment, an example in which a plurality of 1 st intersection portions P1 and 2 nd intersection portions P2 are provided in each of the main flow grooves 31 to 34 and are alternately arranged is described. However, it is not limited thereto. For example, if the main flow channels 31 to 34 include one 1 st intersection P1 and one 2 nd intersection P2, the function of conveying the working fluid 2 can be improved. Further, in each of the main grooves 31 to 34, an example in which the 1 st intersection P1 and the 2 nd intersection P2 are adjacent to each other is described, but the present invention is not limited thereto. For example, in each of the main flow grooves 31 to 34, an intersection (for example, P3 shown in fig. 14) may be formed in which the communication grooves 51 to 54 on both sides are arranged in a straight line between the 1 st intersection P1 and the 2 nd intersection P2 so that the main flow grooves 31 to 34 and the communication grooves 51 to 54 intersect in a cross shape. Even in this case, the function of conveying the liquid working fluid 2 in the fluid channel section 30 can be improved by the 1 st intersection P1 and the 2 nd intersection P2.

In the above-described embodiment, the example in which the 1 st to 4 th main grooves 31 to 34 are orthogonal to the 1 st to 4 th communicating grooves 51 to 54 is described. However, the present invention is not limited to this, and the 1 st to 4 th main grooves 31 to 34 and the 1 st to 4 th communication grooves 51 to 54 may not intersect with each other.

For example, as shown in fig. 15, the direction in which the communication grooves 51 to 54 are arranged may be inclined with respect to the 1 st direction X and the 2 nd direction Y, respectively. In this case, the communication grooves 51 to 54 are inclined at an arbitrary angle θ with respect to the 1 st direction X. In the example shown in fig. 15, the planar shape of each of the convex portions 41a to 44a is a parallelogram. When such a shape is used for the rectangular steam chamber 1, the four

outer edges

1a and 1b (see fig. 2) forming the planar outer contour of the steam chamber 1 are not orthogonal to the communication grooves 51 to 54. In this case, the fold line extending in the 2 nd direction Y can be prevented from being deformed so as to be bent, and the grooves 31 to 34, 51 to 54 of the liquid flow path section 30 can be prevented from being damaged.

The 1 st to 4 th main flow grooves 31 to 34 may not be formed linearly. For example, in fig. 16, the main flow grooves 31 to 34 extend not linearly but meanderingly, and extend globally in the 1 st direction X. More specifically, the pair of

side walls

35 and 36 of the main flow channel 31 are formed so that curved recesses and curved protrusions are alternately arranged and smoothly connected in a continuous manner. When the main flow grooves 31 to 34 shown in fig. 16 are formed, the contact area between the working fluid 2 and the convex portions 41a to 44a is increased, and the cooling efficiency of the working fluid 2 can be improved.

In the above-described embodiment, an example in which the convex portions 41a to 44a are arranged in a zigzag shape over the entire liquid channel portion 30 has been described. However, the present invention is not limited to this, and at least a part of the convex portions 41a to 44a may be arranged in the shape shown in fig. 15 or 16. Further, at least two of the zigzag arrangement shown in fig. 6, the arrangement of fig. 15, and the arrangement of fig. 16 may be combined with the convex portions 41a to 44 a.

In the above-described present embodiment, an example in which the 1 st convex portion 41a, the 2 nd convex portion 42a, the 3 rd convex portion 43a, and the 4 th convex portion 44a have the same shape is described. However, the present invention is not limited to this, and the 1 st to 4 th convex portions 41a to 44a may have different shapes.

For example, as shown in fig. 17, the length of the 2 nd convex portion 42a and the 4 th convex portion 44a in the 1 st direction X may be longer than the length of the 1 st convex portion 41a and the 3 rd convex portion 43 a. In the embodiment shown in fig. 17, two 1 st intersection portions P1 are provided between two 2 nd intersection portions P2 in the 2 nd main flow channel 32 and the 4 th main flow channel 34. That is, as shown in fig. 6, the 1 st intersection P1 and the 2 nd intersection P2 are not alternately arranged. In addition, in the 1 st main flow channel 31 and the 3 rd main flow channel 33, two 2 nd intersection portions P2 are interposed between two 1 st intersection portions P1, and the 1 st intersection portions P1 and the 2 nd intersection portions P2 are not alternately arranged. Even in this case, the function of conveying the liquid working fluid 2 in the fluid channel section 30 can be improved by the 1 st intersection P1 and the 2 nd intersection P2.

In the above-described embodiment, an example in which the upper flow path wall portion 22 of the upper metal sheet 20 extends in an elongated shape along the 1 st direction X of the steam chamber 1 is described. However, the shape of the upper flow path wall 22 is not limited to this. For example, the upper flow path wall 22 may be formed as a columnar boss. Even in this case, it is preferable that the upper flow path wall portion 22 is disposed so as to overlap the lower flow path wall portion 13 in a plan view, and the lower surface 22a of the upper flow path wall portion 22 is in contact with the upper surface 13a of the lower flow path wall portion 13.

In the above-described present embodiment, the example in which the upper metal sheet 20 has the upper steam flow path recessed portion 21 has been described, but the present invention is not limited thereto, and the upper metal sheet 20 may be formed into a flat plate shape as a whole without having the upper steam flow path recessed portion 21. In this case, the lower surface 20a of the upper metal piece 20 abuts as the 2 nd abutment surface against the upper surface 13a of the lower flow path wall portion 13, and the mechanical strength of the steam chamber 1 can be improved.

In the above-described present embodiment, an example in which the lower metal piece 10 has the lower steam flow path concave portion 12 and the liquid flow path portion 30 is described. However, the present invention is not limited to this, and as long as the upper metal sheet 20 has the upper steam flow path recessed portion 21, the lower metal sheet 10 may not have the lower steam flow path recessed portion 12, and the liquid flow path portion 30 may be provided on the upper surface 10a of the lower metal sheet 10. In this case, as shown in fig. 18, the region of the upper surface 10a where the liquid flow path portion 30 is formed may be formed in a region other than the upper flow path wall portion 22, in addition to the region facing the upper flow path wall portion 22, in the region facing the upper steam flow path recessed portion 21. In this case, the number of main grooves 31 to 34 constituting the liquid flow path section 30 can be increased, and the function of conveying the liquid working fluid 2 can be improved. However, the region where the liquid channel section 30 is formed is not limited to the embodiment shown in fig. 18, and may be any region as long as the function of transporting the liquid working liquid 2 can be ensured. In the embodiment shown in fig. 18, in order to secure the steam flow path, the lower surface 22a (contact surface) of the upper flow path wall portion 22 of the upper metal sheet 20 is formed in a partial region of the lower surface 20a of the upper metal sheet 20, and the lower surface 22a of the upper flow path wall portion 22 is in contact with a portion of the region of the upper surface 10a of the lower metal sheet 10 in which the flow path portion 30 is formed.

In the above-described embodiment, the example in which the 1 st to 4 th main flow grooves 31 to 34 include the 1 st intersection P1 and the 2 nd intersection P2 is described. However, without being limited thereto, even if the main flow grooves 31 to 34 do not include the intersecting portions P1 and P2, the ratio of the 1 st to 4 th main flow grooves 31 to 34 to the upper surface 13a of the lower flow passage wall 13 can be increased as long as the width w1 of the 1 st to 4 th main flow grooves 31 to 34 is larger than the width w2 of the 1 st to 4 th protrusions 41a to 44 a. Even in this case, the function of conveying the working fluid 2 can be improved, and the heat transfer efficiency can be improved.

(embodiment 2)

Next, a vapor chamber, an electronic device, a metal sheet for a vapor chamber, and a method for manufacturing a vapor chamber in embodiment 2 of the present invention will be described with reference to fig. 19 to 23.

In embodiment 2 shown in fig. 19 to 23, the other configuration is substantially the same as that of embodiment 1 shown in fig. 1 to 18, except that the width of the 1 st to 4 th communication grooves is larger than that of the 1 st to 4 th main flow grooves. In fig. 19 to 23, the same components as those of embodiment 1 shown in fig. 1 to 18 are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in fig. 19, in the present embodiment, the width w 3' of the 1 st to 4 th communication grooves 51 to 54 is larger than the width w1 of the 1 st to 4 th main flow grooves 31 to 34 (more specifically, the width of the 1 st to 4 th main flow groove main body portions 31a to 34a described later). The width w 3' of the communication grooves 51-54 can be, for example, 40 μm-300 μm. In the present embodiment, as shown in fig. 20 and 21, an example in which the cross-sectional shapes of the main flow grooves 31 to 34 and the cross-sectional shapes of the communication grooves 51 to 54 are formed in a curved shape will be described. In this case, the widths of the grooves 31 to 34, 51 to 54 are set to the width of the groove on the upper surface 13a of the lower flow path wall portion 13. The widths of the projections 41a to 44a described later are also set to the widths of the projections on the upper surface 13a in the same manner.

However, in the present embodiment, the lower surface 22a of the upper flow path wall portion 22 of the upper metal sheet 20 is also formed in a flat shape. Thus, the 1 st to 4 th main flow grooves 31 to 34 of the liquid flow path section 30 are covered with the flat lower surface 22 a. In this case, as shown in fig. 20, the pair of

side walls

35 and 36 extending in the 1 st direction X of the 1 st to 4 th main flow grooves 31 to 34 and the lower surface 22a of the upper flow path wall portion 22 can form two right-angled or acute-angled corner portions 37, and the capillary action of the two corner portions 37 can be improved. That is, even when the cross sections of the 1 st to 4 th main flow grooves 31 to 34 are formed in a curved shape, the capillary action can be improved at the corner 37.

Similarly, the 1 st to 4 th communication grooves 51 to 54 of the liquid channel section 30 are covered with the flat lower surface 22 a. In this case, as shown in fig. 21, the pair of

side walls

55 and 56 extending in the 2 nd direction Y of the 1 st to 4 th communication grooves 51 to 54 and the lower surface 22a of the upper flow path wall portion 22 can form two right-angled or acute-angled corner portions 57, and the capillary action of the two corner portions 57 can be improved. That is, even when the 1 st to 4 th communication grooves 51 to 54 have curved cross sections, the capillary action can be improved at the corner portion 57.

Here, as will be described later, the liquid working fluid 2 condensed from the steam passes through the 1 st to 4 th communication grooves 51 to 54 and enters the 1 st to 4 th main flow grooves 31 to 34. Therefore, by increasing the capillary action of the 1 st to 4 th communication grooves 51 to 54, the condensed liquid working fluid 2 can smoothly enter the 1 st to 4 th main grooves 31 to 34. The condensed liquid working fluid 2 can smoothly enter not only the main flow grooves 31 on the side close to the steam flow path recesses 12 and 21 but also the 1 st to 4 th main flow grooves 31 to 34 on the side away from the steam flow path recesses 12 and 21 by the capillary action of the 1 st to 4 th communication grooves 51 to 54, and the function of transporting the condensed liquid working fluid 2 can be improved. Further, by making the width w 3' of the 1 st to 4 th communication grooves 51 larger than the width w1 of the 1 st to 4 th main flow grooves 31 to 34, the flow path resistance of the working fluid 2 in the 1 st to 4 th communication grooves 51 to 54 can be reduced, and in this regard, the condensed liquid working fluid 2 can be smoothly introduced into the 1 st to 4 th main flow grooves 31 to 34. The working fluid 2 introduced into the 1 st to 4 th main channels 31 to 34 can be smoothly transported toward the evaporation part 11 by the capillary action of the 1 st to 4 th main channels 31 to 34. Therefore, the function of transporting the liquid working fluid 2 can be improved as the whole of the fluid channel section 30.

In addition, both end portions of the 1 st to 4 th convex portions 41a to 44a in the 1 st direction X are rounded in a plan view. That is, although each of the convex portions 41a to 44a is formed in a rectangular shape as viewed globally, a curved portion 45 with rounded corners is provided at the corner portions. Thus, the corners of the respective convex portions 41a to 44a are smoothly curved, and the flow path resistance of the liquid working fluid 2 is reduced. In addition, two bent portions 45 are provided at the right end and the left end of the convex portions 41a to 44a in fig. 19, respectively, and an example in which a linear portion 46 is provided between the two bent portions 45 is shown. Therefore, the 1 st to 4 th communication grooves 51 to 54 have widths w 3' equal to the distance between the linear portions 46 of the convex portions 41a to 44a adjacent to each other in the 1 st direction X. As shown in fig. 6, the same applies to the case where the bent portion 45 is not formed in each of the convex portions 41a to 44 a. However, the end shapes of the convex portions 41a to 44a are not limited to this. For example, the straight portion 46 may not be provided at each of the right and left end portions, and the end portions may be entirely curved (for example, semicircular). The width w 3' of each of the communication grooves 51 to 54 in this case is the minimum distance between the convex portions 41a to 44a adjacent to each other in the 1 st direction X. In fig. 19, the 4 th convex portion 44a shown at the lowermost portion representatively shows a curved portion 45 and a linear portion 46 for clarity of the drawing.

As shown in fig. 20 and 21, in the present embodiment, the depth h 3' of the 1 st to 4 th communication grooves 51 to 54 is greater than the depth h1 of the 1 st to 4 th main flow grooves 31 to 34 (more specifically, the depth of the 1 st to 4 th main flow groove main body portions 31a to 34a described later). Here, as described above, when the cross-sectional shapes of the main flow grooves 31 to 34 and the communication grooves 51 to 54 are formed in a curved shape, the depth of the grooves 31 to 34, 51 to 54 is the depth at the deepest position in the grooves. The depth h 3' of the 1 st to 4 th communication grooves 51 to 54 may be, for example, 10 μm to 250 μm.

In the present embodiment, as shown in fig. 22, the depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 1 st to 4 th main channels 31 to 34 is deeper than the depth h1 of the portion other than the 1 st intersection P1 and the 2 nd intersection P2 in the main channels 31 to 34. That is, the 1 st to 4 th main runner 31 to 34 further include the 1 st to 4 th main runner bodies 31a to 34a provided between the 1 st intersection P1 and the 2 nd intersection P2. The 1 st to 4 th main flow channel main parts 31a to 34a are portions located between the adjacent convex parts 41a to 44a, and are portions located between the 1 st intersection P1 and the 2 nd intersection P2 adjacent to each other. The depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 is deeper than the depth h1 of the 1 st to 4 th main flow channel main bodies 31a to 34 a. The depth h1 'of the 1 st intersection P1 is the depth at the deepest position in the 1 st intersection P1, and the depth h 1' of the 2 nd intersection P2 is the depth at the deepest position in the 2 nd intersection P2.

More specifically, as shown in fig. 19 and 22, the depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 1 st main flow groove 31 is deeper than the depth h1 of the portion (the 1 st main flow groove body 31a) between the 4 th protrusion 44a and the 1 st protrusion 41a in the 1 st main flow groove 31. Similarly, the depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 2 nd main flow groove 32 is deeper than the depth h1 of the portion (the 2 nd main flow groove body portion 32a) between the 1 st projection 41a and the 2 nd projection 42a in the 2 nd main flow groove 32. The depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 3 rd main flow groove 33 is deeper than the depth h1 of the portion (the 3 rd main flow groove body portion 33a) between the 2 nd projection 42a and the 3 rd projection 43a in the 3 rd main flow groove 33. The depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 4 th main flow groove 34 is deeper than the depth h1 of the portion (the 4 th main flow groove body portion 34a) between the 3 rd convex portion 43a and the 4 th convex portion 44a in the 4 th main flow groove 34.

The depth h1 'of the 1 st to 4 th intersection parts P1 and the 2 nd intersection parts P2 of the 1 st to 4 th main grooves 31 to 34 may be deeper than the depth h 3' of the 1 st to 4 th communicating grooves 51 to 54. The depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 may be, for example, 20 μm to 300 μm.

As shown in fig. 19, although the 1 st to 4 th convex portions 41a to 44a are formed in a rectangular shape as viewed globally as described above, they are different from the 1 st to 4 th convex portions 41a to 44a shown in fig. 6 in planar shape. That is, the 1 st to 4 th convex portions 41a to 44a include a pair of 1 st to 4 th convex portion end portions 41b to 44b provided on both sides in the 1 st direction X and 1 st to 4 th convex portion intermediate portions 41c to 44c provided between the pair of 1 st to 4 th convex portion end portions 41b to 44 b. The width w4 of the 1 st to 4 th convex portions intermediate portions 41c to 44c is smaller than the width w2 of the 1 st to 4 th convex portions end portions 41b to 44b (corresponding to the width w2 of the 1 st to 4 th convex portions 41a to 44 a).

More specifically, the width w4 of the 1 st protrusion middle portion 41c is smaller than the width w2 of the 1 st protrusion end portion 41b, and the walls of the 1 st protrusion 41a (i.e., the side wall 36 of the 1 st main flow channel 31 and the side wall 35 of the 2 nd main flow channel 32) are smoothly curved so as to be recessed toward the inside of the 1 st protrusion 41 a. Therefore, the width w4 of the 1 st convex portion intermediate portion 41c is the minimum distance between the two walls. Similarly, the width w4 of the 2 nd protrusion middle portion 42c is smaller than the width w2 of the 2 nd protrusion end portion 42b, and the walls of the 2 nd protrusion 42a (i.e., the side wall 36 of the 2 nd main flow groove 32 and the side wall 35 of the 3 rd main flow groove 33) are smoothly curved so as to be recessed toward the inside of the 2 nd protrusion 42 a. The width w4 of the 3 rd protrusion middle portion 43c is smaller than the width w2 of the 3 rd protrusion end portion 43b, and the walls of the 3 rd protrusion 43a (i.e., the side wall 36 of the 3 rd main flow channel 33 and the side wall 35 of the 4 th main flow channel 34) are smoothly curved so as to be recessed toward the inside of the 3 rd protrusion 43 a. The width w4 of the 4 th protrusion middle portion 44c is smaller than the width w2 of the 4 th protrusion end portion 44b, and the walls of the 4 th protrusion 44a (i.e., the side wall 36 of the 4 th main flow channel 34 and the side wall 35 of the 1 st main flow channel 31) are smoothly curved so as to be recessed toward the inside of the 4 th protrusion 44 a. The width w4 of the 1 st to 4 th convex portion intermediate portions 41c to 44c may be, for example, 15 μm to 175 μm.

As described above, the depth h3 'of the 1 st to 4 th communication grooves 51 to 54 is deeper than the depth h1 of the 1 st to 4 th main flow groove main body portions 31a to 34a of the 1 st to 4 th main flow grooves 31 to 34, and the depth h 1' of the 1 st intersection P1 and the 2 nd intersection P2 of the 1 st to 4 th main flow grooves 31 to 34 is deeper than the depth h1 of the 1 st to 4 th main flow groove main body portions 31a to 34 a. Thus, a buffer region Q deeper than the depth h1 of the 1 st to 4 th main flow channel main bodies 31a to 34a is formed in a region extending from the 2 nd intersection P2 to the 1 st intersection P1 through the 1 st to 4 th communication channels 51 to 54. The buffer area Q can store the liquid working fluid 2.

More specifically, for example, a buffer region Q deeper than the depth h1 of the 1 st main flow channel body 31a and the 2 nd main flow channel body 32a is formed in a region extending from the 2 nd intersection P2 of the 1 st main flow channel 31 to the 1 st intersection P1 of the 2 nd main flow channel 32 via the 1 st communication channel 51. In general, the main flow grooves 31 to 34 and the communication grooves 51 to 54 of the liquid flow path portion 30 are filled with a liquid working fluid 2. Therefore, by making the depth (h1 'and h 3') of the buffer area Q deeper than the depth h1 of the 1 st to 4 th main flow channel main bodies 31a to 34a, a large amount of the working fluid 2 can be retained in the buffer area Q. As described above, since the main flow grooves 31 to 34 and the communication grooves 51 to 54 are filled with the working fluid 2, the working fluid 2 can be retained in the buffer area Q without depending on the posture of the steam chamber 1.

Similarly, a buffer region Q deeper than the depth h1 of the 2 nd main flow channel main body portion 32a and the 3 rd main flow channel main body portion 33a is formed in a region spanning from the 2 nd intersection P2 of the 2 nd main flow channel 32 to the 1 st intersection P1 of the 3 rd main flow channel 33 via the 2 nd communication channel 52. A buffer region Q deeper than the depth h1 of the 3 rd main flow channel main body portion 33a and the 4 th main flow channel main body portion 34a is formed in a region spanning from the 2 nd intersection P2 of the 3 rd main flow channel 33 to the 1 st intersection P1 of the 4 th main flow channel 34 through the 3 rd communication channel 53. In the region where the 2 nd intersection P2 of the 4 th main flow channel 34 extends to the 1 st intersection P1 of the 1 st main flow channel 31 through the 4 th communication channel 54, a buffer region Q is formed that is deeper than the depth h1 of the 4 th main flow channel body 34a and the 1 st main flow channel body 31 a.

Further, although a plurality of 1 st intersections P1 and 2 nd intersections P2 are formed in each liquid flow path section 30 of the steam chamber 1, if the depth h1 'of at least one of the intersections P1 and P2 is deeper than the depth h1 of the main flow channel main bodies 31a to 34a (or the depth h 3' of the communication grooves 51 to 54), the retention performance of the working fluid 2 at the intersections P1 and P2 can be improved. Since the retention performance is improved as the number of the portions of the intersections P1 and P2 of the h1 'deeper than the depth h1 of the main duct bodies 31a to 34a increases, it is preferable that the depths h 1' of all the intersections P1 and P2 be the same. However, it is apparent that the retention performance of the working fluid 2 can be improved even if the depth h 1' of some of the intersections P1 and P2 is deeper than the depth h1 of the main flow channel main bodies 31a to 34a due to manufacturing errors and the like. The same applies to the depth h 3' of the communication grooves 51-54.

Here, a method of confirming the width and depth of the main flow grooves 31 to 34 and the width and depth of the communication grooves 51 to 54 from the completed steam chamber 1 will be described. In general, the main flow grooves 31 to 34 and the communication grooves 51 to 54 are not visible from the outside of the steam chamber 1. Therefore, a method of confirming the width and depth of the main flow grooves 31 to 34 and the communication grooves 51 to 54 from the cross-sectional shape obtained by cutting the completed steam chamber 1 at a desired position is given.

Specifically, the steam chamber 1 was cut into a 10mm square by a cutter to prepare a sample. Then, the sample is vacuum-defoamed and embedded with a resin so that the resin enters the vapor flow path recesses 12 and 21 and the liquid flow path portion 30 (the main flow grooves 31 to 34 and the communication grooves 51 to 54). Next, a dressing process was performed with a diamond knife so as to obtain a desired cross section. At this time, for example, a diamond blade of a microtome (e.g., an ultramicrotome manufactured by Leica Microsystems) is used to trim a portion to be 40 μm from a measurement target position. For example, when the pitch of the communicating grooves 51 to 54 is 200 μm, the communicating grooves 51 to 54 adjacent to each other can be cut by 160 μm to identify the portions 40 μm away from the communicating grooves 51 to 54 for the measurement. Next, the trimmed cut surface was cut to produce a cut surface for observation. At this time, a cross-section sample preparation apparatus (e.g., a cross-section polisher manufactured by JOEL corporation) was used to cut the cut surface by ion beam machining with a projection width of 40 μm, a voltage of 5kV and a time of 6 hours. Then, the cut surface of the obtained sample was observed. At this time, the cut surface was observed using a scanning electron microscope (for example, a scanning electron microscope manufactured by Cardo-Zeiss corporation) with a voltage of 5kV, a working distance of 3mm, and an observation magnification of 200 times or 500 times. Thus, the widths and depths of the main grooves 31 to 34 and the communication grooves 51 to 54 can be measured. The observation magnification standard during imaging is referred to as polar 545. The above-described method is an example, and the apparatus to be used, the measurement conditions, and the like can be arbitrarily determined according to the shape, structure, and the like of the sample.

However, as described above, the 1 st to 4 th communication grooves 51 to 54 have widths w 3' larger than the widths w1 of the 1 st to 4 th main flow grooves 31 to 34. Thus, the buffer area Q is an area having an opening larger than the 1 st to 4 th main flow channel main body portions 31a to 34 a. Therefore, in the 2 nd half etching step shown in fig. 10, the etching liquid enters the buffer region Q more than the 1 st to 4 th main flow cell main bodies 31a to 34 a. As a result, erosion by the etching liquid in the buffer region Q advances, and the depth of the buffer region Q becomes deeper. In addition, since the portions of the buffer area Q corresponding to the 1 st intersection P1 and the 2 nd intersection P2 communicate with the 1 st to 4 th main flow channel main bodies 31a to 34a, the etching solution easily enters the 1 st to 4 th communication channels 51 to 54. Thus, the depth h1 'of the 1 st intersection P1 and the 2 nd intersection P2 can be deeper than the depth h 3' of the 1 st to 4 th communication grooves 51 to 54. Thus, the buffer region Q is formed as shown in fig. 22.

Further, the etching liquid enters the buffer region Q in a large amount, and thus erosion by the etching liquid advances in the portions of the walls of the 1 st to 4 th protrusions 41a to 44a (the

side walls

35 and 36 of the 1 st to 4 th main flow grooves 31 to 34) facing the 1 st intersection P1 and the 2 nd intersection P2. As a result, the walls of the projections 41a to 44a are eroded by the etching liquid, and are formed into a smoothly curved shape so as to be recessed toward the inside of the projections 41a to 44 a.

In the second half etching step shown in fig. 10, as described above, the second resist film 2 is formed in a pattern on the upper surface 13a of the lower flow path wall portion 13, and the etching solution enters the resist opening of the second resist film 2 to form the first to second main flow grooves 31 to 34 and the first to second communication grooves 51 to 54. Even when the resist opening is formed parallel to the 1 st direction X and the 2 nd direction Y, the width w 3' of the 1 st to 4 th communication grooves 51 to 54 is larger than the width w1 of the 1 st to 4 th main flow grooves 31 to 34, and therefore, the etching solution easily enters the buffer region Q. Therefore, the buffer region Q can be formed as described above.

In the steam chamber 1 of the present embodiment, the steam of the working fluid 2 diffused to the peripheral portion of the steam chamber 1 is cooled and condensed. The condensed liquid working fluid 2 enters the main channel 31 through the 1 st to 4 th communication channels 51 to 54. Here, as described above, the width w 3' of the 1 st to 4 th communication grooves 51 to 54 is larger than the width w1 of the 1 st to 4 th main grooves 31 to 34, and therefore the flow resistance of the working fluid 2 in the communication grooves 51 to 54 is reduced. Therefore, the liquid working fluid 2 adhering to the wall surfaces of the steam flow path recesses 12 and 21 smoothly enters the main flow grooves 31 to 34 through the communication grooves 51 to 54. The main flow grooves 31 to 34 and the communication grooves 51 to 54 are filled with a liquid working fluid 2.

When the working fluid 2 filled in each of the main channels 31 to 34 is transported to the evaporation unit 11, a part of the working fluid 2 passes through the 1 st intersection P1 and the 2 nd intersection P2 and is directed toward the evaporation unit 11. In the 1 st intersection portion P1 and the 2 nd intersection portion P2, the working fluid 2 is mainly pushed toward the evaporation portion 11 by the capillary action of the corner 37 formed by the

side walls

35 and 36 of the 1 st to 4 th main flow grooves 31 to 34 and the lower surface 22a of the upper flow passage wall 22.

On the other hand, a part of the working fluid 2 directed to the evaporation unit 11 is introduced into and retained in the buffer region Q formed by the 1 st intersection P1 or the 2 nd intersection P2.

Here, when dry-up occurs in the 1 st to 4 th main flow channel main bodies 31a to 34a, the working fluid 2 stored in the buffer area Q moves to the dry-up generating portion. More specifically, for example, when dry-up occurs in the 1 st main flow channel body 31a, the operating fluid 2 moves from the buffer area Q closest to the dry-up generating portion by the capillary action of the 1 st main flow channel body 31 a. Thereby, the generation part of the dry-up is filled with the working fluid 2 to eliminate the dry-up.

Further, in the case where bubbles generated by the vapor are generated in the liquid working fluid 2 in the 1 st to 4 th main flow channel main body portions 31a to 34a, the bubbles are introduced into and held in the buffer region Q on the downstream side (the evaporation portion 11 side). Since the depth of the buffer area Q is deeper than the depth h1 of the 1 st to 4 th main flow channel main bodies 31a to 34a, the movement of the air bubbles introduced into the buffer area Q from the buffer area Q to the main flow channel main bodies 31a to 34a is suppressed. Therefore, the air bubbles generated in the main flow channel main bodies 31a to 34a can be captured by the buffer area Q, and the flow of the working fluid 2 to the evaporation portion 11 can be suppressed from being hindered by the air bubbles.

Thus, according to the present embodiment, the 1 st to 4 th communication grooves 51 to 54 have a width w 3' greater than the width w1 of the 1 st to 4 th main flow grooves 31 to 34. This can reduce the flow path resistance of the working fluid 2 in each of the communication grooves 51 to 54. Therefore, the liquid working fluid 2 condensed from the steam can smoothly enter the main flow grooves 31 to 34. That is, the condensed liquid working fluid 2 can be more efficiently transported by not only the main flow grooves 31 to 34 on the side closer to the steam flow path recesses 12 and 21 but also the main flow grooves 31 to 34 on the side farther from the steam flow path recesses 12 and 21. As a result, the function of transporting the liquid working fluid 2 can be improved, and the heat transport efficiency can be improved.

In addition, according to the present embodiment, the depth h 3' of the 1 st to 4 th communication grooves 51 to 54 is deeper than the depth h1 of the 1 st to 4 th main flow grooves 31 to 34. Thus, the buffer areas Q for storing the working fluid 2 can be formed in the respective communication grooves 51 to 54. Therefore, when dry-out occurs in the main flow channels 31 to 34, the working fluid 2 stored in the buffer area Q can be moved to the dry-out generation portion. Therefore, the drying can be eliminated, and the function of conveying the working fluid 2 in each main flow channel 31 to 34 can be restored. When bubbles are generated in the main flow channels 31 to 34, the bubbles can be introduced into the buffer area Q and trapped. In this regard, the function of conveying the working fluid 2 in each main flow channel 31 to 34 is restored.

In addition, according to the present embodiment, the depth h 1' of the 1 st to 4 th intersection P1 and the 2 nd intersection P2 of the 1 st to 4 th main flow grooves 31 to 34 is deeper than the depth h1 of the 1 st to 4 th main flow groove main body portions 31a to 34 a. This allows the buffer area Q to extend to the 1 st intersection P1 and the 2 nd intersection P2. Therefore, the reserve amount of the working fluid 2 in the buffer area Q can be increased, and the dry-up can be eliminated more easily.

In addition, according to the present embodiment, the depth h1 'of the 1 st to 4 th intersection P1 and the 2 nd intersection P2 of the 1 st to 4 th main grooves 31 to 34 is deeper than the depth h 3' of the 1 st to 4 th communicating grooves 51 to 54. This makes it possible to increase the depth of the buffer area Q on the side of the buffer area Q close to the dry-up generating portion. Therefore, the stored working fluid 2 can be smoothly moved to the dry generation portion, and the dry can be more easily eliminated.

In addition, according to the present embodiment, the 1 st to 4 th convex portions 41a to 44a have the width w4 of the 1 st to 4 th convex portion intermediate portions 41c to 44c smaller than the width w2 of the 1 st to 4 th convex portion end portions 41b to 44 b. This can increase the planar area of the 1 st intersection P1 and the 2 nd intersection P2. Therefore, the reserve amount of the working fluid 2 in the buffer area Q can be increased, and the dry-up can be eliminated more easily.

In addition, according to the present embodiment, the corner portions of the respective convex portions 41a to 44a are provided with the curved portions 45 with rounded corners. This makes it possible to smoothly curve the corners of the respective convex portions 41a to 44a, and to reduce the flow path resistance of the liquid working fluid 2.

(embodiment 3)

Next, a steam chamber, a metal sheet for a steam chamber, and a method for manufacturing a steam chamber in embodiment 3 of the present invention will be described with reference to fig. 23 to 25.

In embodiment 3 shown in fig. 23 to 25, the main flow groove convex portion mainly protrudes into the 1 st to 4 th main flow grooves, and the communication groove convex portion protrudes into the 1 st to 4 th communication grooves, but the other configurations are substantially the same as those of embodiment 2 shown in fig. 19 to 22. In fig. 23 to 25, the same components as those in embodiment 2 shown in fig. 19 to 22 are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in fig. 23, in the present embodiment, the upper metal sheet 20 has a plurality of main flow groove projections 27 provided on the lower surface 20 a. The main flow groove protrusions 27 protrude from the lower surface 20a toward the corresponding main flow grooves 31 to 34 of the 1 st to 4 th main flow grooves 31 to 34 of the lower metal sheet 10. The lower end of the main channel projection 27 is separated from the bottom of the main channels 31 to 34, and a flow path of the working fluid 2 is ensured. In addition, each main flow groove convex part 27 is formed to extend along the corresponding main flow groove 31-34 in the 1 st direction X.

The main flow channel protrusion 27 is formed in a curved shape in cross section. The side edges of the main flow groove convex portions 27 are in contact with or close to the

side walls

35, 36 of the 1 st to 4 th main flow grooves 31 to 34. Thus, the corner 37 formed by the

side walls

35, 36 of the 1 st to 4 th main flow grooves 31 to 34 and the lower surface 22a of the upper flow passage wall 22 is formed in a wedge shape (or an acute angle shape). Thus, as shown in fig. 23, the flow path cross section defined by the main flow grooves 31 to 34 and the main flow groove protrusion 27 (flow path cross section in the 2 nd direction Y) is formed in a crescent shape.

As shown in fig. 24 and 25, in the present embodiment, the upper metal sheet 20 has a plurality of communication groove protrusions 28 provided on the lower surface 20 a. The communication groove convex portions 28 protrude from the lower surface 20a toward the corresponding communication grooves 51 to 54 of the 1 st to 4 th communication grooves 51 to 54 of the lower metal sheet 10. The lower end of the communication groove protrusion 28 is separated from the bottom of the communication grooves 51 to 54, and a flow path for the working fluid 2 is ensured. Further, each of the communication groove protrusions 28 is formed to extend in the 2 nd direction Y along the corresponding communication groove 51-54. In the 1 st intersection portion P1 and the 2 nd intersection portion P2 of the 1 st to 4 th main grooves 31 to 34, the main groove convex portion 27 and the communication groove convex portion 28 intersect in a T-shape.

The cross section of the communication groove convex portion 28 is formed in a curved shape like the main flow groove convex portion 27. The side edges of the communication groove convex portion 28 are in contact with or close to a pair of side walls 55 and 56 (see fig. 19) extending in the 2 nd direction Y of the 1 st to 4 th communication grooves 51 to 54. Thus, the corner 57 formed by the

side walls

55 and 56 of the 1 st to 4 th communication grooves 51 to 54 and the lower surface 22a of the upper flow path wall 22 is formed in a wedge shape (or an acute angle shape). Thus, as shown in FIG. 24, the cross section of the flow path defined by the communication grooves 51 to 54 and the communication groove convex portion 28 (cross section of the flow path in the 1 st direction X) is crescent-shaped. The flow path cross section in the 2 nd direction Y is formed in the flow path cross section in the 2 nd direction Y in which the 1 st to 4 th communication grooves 51 to 54 are interposed between the flow path cross sections of the main flow grooves 31 to 34 shown in fig. 23, and therefore, as shown in fig. 25, the flow path cross section in the 2 nd direction Y is formed in an elongated crescent shape. In fig. 19, for the sake of clarity of the drawing,

reference numerals

55 and 56 are given only to the side walls of the 3 rd communication groove 53. The

side walls

55, 56 correspond to the linear portions 46 of the projections 41a to 44 a.

The main flow groove convex portion 27 and the communication groove convex portion 28 can be formed by, for example, half-etching the upper metal sheet 20 to form the upper flow passage wall portion 22 and the like, and then pressing the upper metal sheet 20 alone. Alternatively, in the permanent joining step shown in fig. 12, the main flow groove convex portion 27 and the communication groove convex portion 28 can be formed by increasing the pressing force applied to the lower metal sheet 10 and the upper metal sheet 20. That is, by increasing the pressurizing force, a part of the upper flow path wall portion 22 of the upper metal sheet 20 can be inserted into the 1 st to 4 th main flow grooves 31 to 34 and the 1 st to 4 th communication grooves 51 to 54, and thereby the main flow groove convex portion 27 and the communication groove convex portion 28 having curved cross sections can be formed.

Thus, according to the present embodiment, the main flow groove protrusion 27 protrudes from the lower surface 20a of the upper metal piece 20 toward the corresponding main flow grooves 31 to 34 of the 1 st to 4 th main flow grooves 31 to 34 of the lower metal piece 10. This makes it possible to form the corner 37 formed by the

side walls

35 and 36 of the 1 st to 4 th main flow grooves 31 to 34 and the lower surface 22a of the upper flow passage wall 22 as a minute space defined by the

side walls

35 and 36 of the 1 st to 4 th main flow grooves 31 to 34 and the main flow groove convex portion 27. Therefore, the capillary action of the corner portion 37 can be improved. As a result, the function of conveying the liquid working fluid 2 in each main flow channel 31 to 34 can be improved, and the heat transfer efficiency can be improved. In particular, even when the 1 st intersection P1 and the 2 nd intersection P2 of the main channels 31 to 34 are configured as the buffer region Q as shown in fig. 19, the working fluid 2 at the 1 st intersection P1 and the 2 nd intersection P2 can be applied with a high propulsive force toward the evaporation portion 11 by the capillary action of the main channel convex portion 27, and the function of transporting the working fluid 2 can be effectively improved.

Further, according to the present embodiment, the main flow groove protrusion 27 is formed in a curved shape in cross section. This makes it possible to form the corner 37 into a crescent-shaped end. Therefore, the capillary action of the corner portion 37 can be further improved.

Further, according to the present embodiment, the communication groove convex portion 28 protrudes from the lower surface 20a of the upper metal sheet 20 toward the corresponding communication groove 51 to 54 of the 1 st to 4 th communication grooves 51 to 54 of the lower metal sheet 10. This makes it possible to form the corner 57 formed by the

side walls

55 and 56 of the 1 st to 4 th communication grooves 51 to 54 and the lower surface 22a of the upper flow path wall portion 22 into a minute space defined by the

side walls

55 and 56 of the 1 st to 4 th communication grooves 51 to 54 and the communication groove convex portion 28. Therefore, the capillary action of the corner portion 57 can be improved.

Here, as described above, the liquid working fluid 2 condensed from the steam passes through the 1 st to 4 th communication grooves 51 to 54 and enters the 1 st to 4 th main flow grooves 31 to 34. Therefore, by increasing the capillary action of the 1 st to 4 th communication grooves 51 to 54, the condensed liquid working fluid 2 can smoothly enter the 1 st to 4 th main grooves 31 to 34. The condensed liquid working fluid 2 can smoothly enter the main grooves 31 to 34 on the side close to the steam flow path recesses 12 and 21 and can also smoothly enter the main grooves 31 to 34 on the side away from the steam flow path recesses 12 and 21 by the capillary action of the 1 st to 4 th communication grooves 51 to 54, and the function of transporting the condensed liquid working fluid 2 can be improved. Further, by setting the width w 3' of the 1 st to 4 th communication grooves 51 to 54 to be larger than the width w1 of the 1 st to 4 th main flow grooves 31 to 34, the flow path resistance of the working fluid 2 in the 1 st to 4 th communication grooves 51 to 54 can be reduced, and in this respect, the condensed liquid working fluid 2 can be smoothly introduced into the 1 st to 4 th main flow grooves 31 to 34. The working fluid 2 having entered the 1 st to 4 th main channels 31 to 34 can be smoothly transferred to the evaporation part 11 by the capillary action of the 1 st to 4 th main channels 31 to 34. Therefore, the function of transporting the liquid working fluid 2 can be improved as the whole of the fluid channel section 30. Further, as described above, when the drying-up occurs due to the improvement of the capillary action of the 1 st to 4 th communication grooves 51 to 54, the working fluid 2 can be moved between the 1 st to 4 th main grooves 31 to 34 by the capillary action of the 1 st to 4 th communication grooves 51 to 54, and the drying-up can be eliminated.

Further, according to the present embodiment, the communication groove convex portion 28 is formed in a curved shape in cross section. This allows the corner portion 57 to have a crescent-shaped end portion. Therefore, the capillary action of the corner portion 57 can be further improved.

In the above-described embodiment, the example in which the cross sections of the 1 st to 4 th main grooves 31 to 34 and the cross sections of the 1 st to 4 th communication grooves 51 to 54 are formed in the curved shape is described. However, the present invention is not limited thereto, and the cross sections of the 1 st to 4 th main flow grooves 31 to 34 and the cross sections of the 1 st to 4 th communication grooves 51 to 54 may be formed in a rectangular shape as shown in FIG. 7. Even in this case, the capillary action of the

corner portions

37 and 57 can be improved, and the function of transporting the liquid working fluid 2 in the 1 st to 4 th main channels 31 to 34 and the 1 st to 4 th communication channels 51 to 54 can be improved. The main flow grooves 31 to 34 and the communication grooves 51 to 54 are preferably formed by press working or cutting so that the cross section is rectangular.

In the above-described embodiment, the example in which the width w 3' of the 1 st to 4 th communication grooves 51 to 54 is larger than the width w1 of the 1 st to 4 th main flow grooves 31 to 34 is described. However, the width w 3' of the communication grooves 51 to 54 is not limited to this, and may be not greater than the width w1 of the main flow grooves 31 to 34, as shown in FIG. 6. That is, the main channel convex portions 27 enhance the capillary action of the 1 st to 4 th main channels 31 to 34, and the effect of enhancing the function of transporting the liquid working fluid 2 in the main channels 31 to 34 can be exhibited regardless of the magnitude relation between the width w 3' of the communication channels 51 to 54 and the width w1 of the main channels 31 to 34. Similarly, the effect of improving the function of transporting the condensed liquid working fluid 2 can be exhibited regardless of the magnitude relationship between the width w 3' of the communication grooves 51 to 54 and the width w1 of the main grooves 31 to 34 by improving the capillary action of the 1 st to 4 th communication grooves 51 to 54 by the communication groove convex portion 28.

The present invention is not limited to the above-described embodiments and modifications, and can be embodied by modifying the components in the implementation stage without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of constituent elements disclosed in the above embodiments and modifications. Some of the components may be deleted from all the components shown in the embodiments and the modifications. In the above embodiments and modifications, the configuration of the lower metal sheet 10 and the configuration of the upper metal sheet 20 may be reversed.

Claims

1. A steam chamber, in which a working fluid is sealed, includes:

1 st metal sheet;

the 2 nd metal sheet is arranged on the 1 st metal sheet; and

the 2 nd main flow channel includes: a 1 st intersection portion in which at least a part of the 1 st communication groove faces the 2 nd convex portion; and a 2 nd intersecting portion in which at least a part of the 2 nd communicating groove faces the 1 st convex portion,

the width of the 2 nd communication groove is larger than the width of the 2 nd main flow groove and the width of the 3 rd main flow groove,

2. The vapor cell of claim 1,

3. The vapor cell of claim 2,

4. A steam chamber as claimed in any one of claims 1 to 3,

5. A steam chamber as claimed in any one of claims 1 to 3,

6. A steam chamber as claimed in any one of claims 1 to 3,

the 3 rd main flow channel comprises: a 1 st intersection portion in which at least a part of the 2 nd communication groove faces the 3 rd convex portion; and a 2 nd intersection portion in which at least a part of the 3 rd communication groove faces the 2 nd convex portion.

7. The vapor cell of claim 6,

8. The vapor cell of claim 6,

9. A steam chamber as claimed in any one of claims 1 to 3,

10. A steam chamber as claimed in any one of claims 1 to 3,

11. A steam chamber as claimed in any one of claims 1 to 3,

12. An electronic device is provided with:

a housing;

a device housed within the housing; and

a vapor chamber as claimed in any of claims 1 to 11, in thermal contact with the device.

13. A metal sheet for a steam chamber, used in a steam chamber, which is sealed with a working fluid and has a sealed space including a steam passage section through which steam of the working fluid passes and a liquid passage section through which the liquid working fluid passes,

the metal sheet for a steam chamber includes:

the 1 st surface; and

a 2 nd surface provided on the opposite side of the 1 st surface,

the liquid channel part is provided on the 1 st surface,

14. A method for manufacturing a steam chamber having a sealed space which is provided between a 1 st metal piece and a 2 nd metal piece and in which a working fluid is sealed, the steam chamber including a steam passage portion through which steam of the working fluid passes and a liquid passage portion through which the liquid working fluid passes,

the method for manufacturing the steam chamber comprises the following steps:

a sealing step of sealing the working fluid in the sealed space,